1.
How much work was done if 5 N of force was used to move an object 25 meters?
Correct Answer
B. 125 Joules
Explanation
The work done can be calculated using the formula W = F * d, where W is the work done, F is the force applied, and d is the distance moved. In this case, the force applied is 5 N and the distance moved is 25 meters. Plugging these values into the formula, we get W = 5 N * 25 m = 125 Joules.
2.
Which of the following statements are true about work?
Correct Answer
A. Work is a form of energy.
Explanation
Work is a form of energy, and in fact it has units of energy.
3.
Which of the following statements are true about potential energy?
Correct Answer
C. Potential energy is the energy stored in an object due to its position.
Explanation
This is the definition of potential energy.
4.
An arrow is drawn back so that 50 Joules of potential energy is stored in the stretched bow and string. When released, the arrow will have a kinetic energy of ____ Joules.
Correct Answer
A. 50
Explanation
When the arrow is drawn back and 50 Joules of potential energy is stored in the stretched bow and string, this potential energy is converted into kinetic energy when the arrow is released. According to the law of conservation of energy, the total energy remains constant. Therefore, the arrow will have the same amount of kinetic energy as the potential energy stored, which is 50 Joules.
5.
A job is done slowly, and an identical job is done quickly. Both jobs require the same amount of ____, but different amounts of ____.
Correct Answer
A. Work, power
Explanation
In this scenario, the correct answer is "work, power". Work refers to the amount of energy transferred or expended in completing a task, and in both cases, the jobs require the same amount of work. However, power is the rate at which work is done or the amount of work done per unit of time. Since one job is done slowly and the other quickly, it implies that the quick job requires more power to complete the same amount of work in a shorter time.
6.
What is kinetic energy?
Correct Answer
A. The energy an object has due to its motion
Explanation
Kinetic energy is defined as the energy that an object possesses due to its motion. It is directly proportional to the mass of the object and the square of its velocity. When an object is in motion, it possesses kinetic energy because it has the ability to do work or cause a change in its surroundings. The faster the object moves or the heavier it is, the greater its kinetic energy will be. Therefore, the correct answer is "the energy an object has due to its motion."
7.
What would have the greatest kinetic energy?
Correct Answer
A. A car driving down a hill
Explanation
A car driving down a hill would have the greatest kinetic energy because it has the most mass and can reach higher speeds compared to a person running or a ball rolling down a hill. Kinetic energy is directly proportional to an object's mass and the square of its velocity, so a car with its larger mass and potentially higher velocity would possess the greatest kinetic energy.
8.
A force that causes a change in motion is ...
Correct Answer
D. Unbalanced
Explanation
Unbalanced force is the correct answer because it refers to a force that causes a change in motion. When there is an unbalanced force acting on an object, it will accelerate or decelerate, causing a change in its velocity. This force can be in any direction and its magnitude is greater than the opposing forces, resulting in a net force and a change in motion.
9.
All of the forces that act on an object add up to equal...
Correct Answer
A. Net Force
Explanation
When multiple forces act on an object, they can either cancel each other out or combine to create a net force. The net force is the overall force acting on the object, taking into account both the direction and magnitude of each individual force. It determines the object's acceleration according to Newton's second law of motion (F = ma), where F represents the net force and a represents the acceleration. Therefore, the correct answer is "Net Force."
10.
A force that acts in opposition to motion is called...
Correct Answer
B. Friction
Explanation
Friction is the correct answer because it is a force that acts in opposition to motion. When two surfaces come into contact, friction occurs, causing resistance to the motion. Friction can be observed in various situations, such as when walking on a rough surface or rubbing hands together. It is an essential force in everyday life, as it helps to prevent objects from sliding or slipping easily.
11.
The units for Power are?
Correct Answer
A. Watts
Explanation
Power is a measure of the rate at which work is done or energy is transferred. It is calculated by dividing the amount of work done or energy transferred by the time taken. The unit for power is Watts, which is equivalent to one joule per second. Watts is the correct answer because it is the standard unit used to measure power in the International System of Units (SI). Hertz is the unit for frequency, Pascals is the unit for pressure, and Decibels is the unit for sound intensity.
12.
If an object has kinetic energy, then it also must have _____.
Correct Answer
A. Speed/velocity
Explanation
If an object has kinetic energy, it means that it is in motion. Speed/velocity is a measure of how fast an object is moving, so if an object has kinetic energy, it must also have speed/velocity. Impulse, acceleration, and force are not directly related to an object having kinetic energy.
13.
The tendency of an object to resist changes in its velocity is called:
Correct Answer
D. Inertia
Explanation
Inertia is the tendency of an object to resist changes in its velocity. It is a property of matter that causes objects to stay at rest or continue moving in a straight line at a constant speed unless acted upon by an external force. Inertia is related to an object's mass, with larger objects having greater inertia. It is the reason why we feel a force pushing us backwards when a car suddenly accelerates or why we continue moving forward when a car suddenly stops. Inertia is a fundamental concept in physics and is essential for understanding the behavior of objects in motion.
14.
In order for work to be done there must be _________________________.
Correct Answer
C. Movement parallel to force
Explanation
In order for work to be done, there must be movement parallel to force. This is because work is defined as the product of force and displacement in the direction of the force. If there is no movement parallel to the force, no work is being done, regardless of the presence of mass, power, or time.
15.
Your "weight" is properly defined as
Correct Answer
B. The gravitational force which Earth exerts on you
Explanation
The correct answer is "the gravitational force which Earth exerts on you." This is because weight is a measure of the force of gravity acting on an object. It is dependent on the mass of the object and the acceleration due to gravity. In this case, the weight is defined as the force exerted by the Earth on the person, causing them to experience a downward force.
16.
A push or a pull on matter is called a ...
Correct Answer
D. Force
Explanation
Force is the correct answer because a push or a pull on matter is defined as a force. Force is a vector quantity that can cause an object to accelerate, decelerate, or change direction. It is measured in units of Newtons (N) and can be exerted by both living organisms and inanimate objects. In the context of physics, force is a fundamental concept that plays a crucial role in understanding the motion and interactions of objects in the universe.
17.
Forces that do not cause changes in motion are ....
Correct Answer
B. Balanced
Explanation
Balanced forces are forces that are equal in magnitude and opposite in direction, resulting in no net force acting on an object. These forces do not cause changes in motion because they cancel each other out, keeping the object in a state of equilibrium. In other words, the object will remain at rest if it was initially at rest, or it will continue moving at a constant velocity if it was already in motion. Therefore, balanced forces do not cause any acceleration or changes in the object's motion.
18.
How much matter is in an object is measured by
Correct Answer
B. Mass
Explanation
Mass is the measure of the amount of matter in an object. It is a fundamental property of an object and is independent of its location. Mass can be measured using a balance or a scale, and it is usually expressed in units such as grams or kilograms. Volume, temperature, and weight are not direct measurements of the amount of matter in an object.
19.
Newton's 2nd Law is about...
Correct Answer
A. Force, Mass, and Acceleration
Explanation
Newton's 2nd Law states that the acceleration of an object is directly proportional to the net force applied to it and inversely proportional to its mass. This means that the greater the force applied to an object, the greater its acceleration will be, and the greater the mass of an object, the smaller its acceleration will be. Therefore, Newton's 2nd Law is about the relationship between force, mass, and acceleration.
20.
If an object is moving at a constant velocity, the forces on it are:-
Correct Answer
D. Balanced
Explanation
If an object is moving at a constant velocity, it means that there is no net force acting on it. This implies that the forces on the object are balanced, meaning that the forces in one direction are equal and opposite to the forces in the opposite direction. Therefore, the correct answer is "Balanced".
21.
If a bicycle and rider of mass 80kg is accelerating at 1.5m/s^{2 }the force pushing it is:-
Correct Answer
C. 120N
Explanation
The force pushing the bicycle and rider can be determined using Newton's second law, which states that force is equal to mass multiplied by acceleration. In this case, the mass is given as 80kg and the acceleration is 1.5m/s2. Therefore, the force pushing the bicycle and rider is 80kg Ã— 1.5m/s2 = 120N.
22.
A motorcyclist of mass 250kg accelerates from rest to 20m/s in 4s. What is the force from the engine?
Correct Answer
A. 1250N
Explanation
The force from the engine can be calculated using Newton's second law of motion, which states that force is equal to mass multiplied by acceleration. In this case, the mass of the motorcyclist is given as 250kg and the acceleration is the change in velocity divided by the time taken, which is (20m/s - 0m/s) / 4s = 5m/s^2. Therefore, the force from the engine is 250kg * 5m/s^2 = 1250N.
23.
A seatbelt brings a passenger to a stop from 12m/s in just 2s. If the passenger has a mass of 60kg, what is the force exerted by the seatbelt?
Correct Answer
B. 360N
Explanation
When a passenger is brought to a stop by a seatbelt, the force exerted by the seatbelt can be calculated using Newton's second law, which states that force is equal to mass multiplied by acceleration. In this case, the passenger's mass is given as 60kg. The acceleration can be calculated using the formula acceleration = (final velocity - initial velocity) / time. The initial velocity is given as 12m/s and the time is given as 2s. Substituting these values into the formula, we get acceleration = (0 - 12) / 2 = -6m/s^2. Since the passenger is being brought to a stop, the acceleration is negative. Finally, we can calculate the force using the formula force = mass * acceleration. Substituting the values, we get force = 60kg * (-6m/s^2) = -360N. The negative sign indicates that the force is acting in the opposite direction to the motion. However, since the question asks for the magnitude of the force, the answer is 360N.
24.
Which of the following conditions have to be true when a parachutist reaches Terminal Velocity
Correct Answer
A. The forces on her must be balanced
Explanation
When a parachutist reaches terminal velocity, the forces on her must be balanced. This means that the force of gravity pulling her downwards must be equal to the force of air resistance pushing against her. At terminal velocity, the parachutist is falling at a constant speed because the opposing forces are equal. If the forces were not balanced, the parachutist would either continue to accelerate or decelerate. Therefore, for the parachutist to reach terminal velocity, the forces on her must be balanced.
25.
Does the speedometer of a car read average speed or
instantaneous speed?
Correct Answer
B. Instantaneous speed
Explanation
The speedometer of a car reads instantaneous speed. This means that it shows the speed of the car at any given moment. It provides real-time information about how fast the car is currently moving. In contrast, average speed is calculated by dividing the total distance traveled by the total time taken. The speedometer cannot provide information about average speed as it only shows the speed at a particular instant.
26.
1. ______ is a unit of speed:
Correct Answer
A. M/s
Explanation
m/s is a unit of speed because it represents the distance traveled in meters divided by the time taken in seconds. This unit is commonly used in scientific and everyday contexts to measure the rate at which an object or person is moving. It indicates the number of meters covered in one second, providing a standard measurement for comparing speeds.
27.
3. If a total distance of 750 m is covered in a
time interval of 25 s,the average speed is ______?â€¨
Correct Answer
D. 30 m/s
Explanation
The average speed is calculated by dividing the total distance covered by the time taken. In this case, the total distance covered is 750 m and the time interval is 25 s. Dividing 750 m by 25 s gives us an average speed of 30 m/s.
28.
4. ______________ describes how fast something is
going, whereas, __________ describes how fast something is going and in a
certain direction.â€¨
Correct Answer
A. Speed, velocity
Explanation
Speed is a scalar quantity that describes how fast something is going, while velocity is a vector quantity that describes both the speed and direction of motion. In other words, speed only considers the magnitude of the motion, whereas velocity takes into account both magnitude and direction.
29.
5. Which of the following is a measure of velocity?
Correct Answer
D. 30 m/s, South
Explanation
The correct answer is 30 m/s, South. Velocity is a measure of how fast an object is moving in a specific direction. In this case, the answer includes both the speed (30 m/s) and the direction (South), making it a measure of velocity.
30.
6. If a person walked at 2 m/s for 12 s he/she
would travel a distance of ________.
Correct Answer
A. 24 m
Explanation
If a person walked at a speed of 2 m/s for 12 seconds, the distance traveled can be calculated by multiplying the speed by the time. Therefore, 2 m/s multiplied by 12 seconds equals 24 meters.
31.
7. How long would it take to travel 50 km traveling
at a speed of 10 km/hr?â€¨
Correct Answer
C. 5 hours
Explanation
At a speed of 10 km/hr, it would take 5 hours to travel 50 km. This can be calculated by dividing the distance (50 km) by the speed (10 km/hr), which equals 5 hours.
32.
10. How far would you travel moving at 12 m/s for
3.00 minutes?â€¨
Correct Answer
B. 2160 m
Explanation
At a speed of 12 m/s, the distance covered in 1 second would be 12 meters. Therefore, in 3 minutes (which is equal to 3 x 60 = 180 seconds), the distance covered would be 12 x 180 = 2160 meters.
33.
What is the unit of weight?
Correct Answer
D. Newton
Explanation
Weight is a force and it is measured in newton.
34.
What is the unit of force?
Correct Answer
C. Newton
Explanation
Force is measured in Newton.
35.
Which of the following is not an effect of force?
Correct Answer
D. Force can reduce the mass of an object.
Explanation
Force cannot change the mass of an object.
36.
What is the dependent variable in this question: If we make the walls of a boat higher, will it float longer?
Correct Answer
D. How long it floats
Explanation
The dependent variable in this question is "how long it floats." This means that the duration for which the boat remains afloat is the factor being measured and observed. By increasing the height of the walls of the boat, the question aims to investigate if there is a correlation between wall height and the duration of floating.
37.
What is the independent variable? If we add more icing to a cake, will it produce mold faster?
Correct Answer
C. Amount of icing
Explanation
The independent variable in this scenario is the amount of icing. This is because it is the factor that is being manipulated or changed in order to observe its effect on the dependent variable, which in this case is the rate of mold growth on the cake. By adding more icing, the experiment aims to determine whether there is a correlation between the amount of icing and the speed at which mold develops on the cake.
38.
A 2 kg block is dropped from the roof of a tall building at the same time a 6 kg ball is thrown horizontally from the same height. Which statement best describes the motion of the block and the motion of the ball? (ignore air resistance)
Correct Answer
D. The block and the ball hit the ground at the same time because they have the same vertical acceleration
Explanation
The block and the ball hit the ground at the same time because they have the same vertical acceleration. The mass of an object does not affect its vertical acceleration due to gravity. In the absence of air resistance, all objects near the surface of the Earth experience the same acceleration due to gravity, which is approximately 9.8 m/s^2. Therefore, both the block and the ball will fall with the same acceleration and hit the ground at the same time, regardless of their mass or horizontal velocity.
39.
A student is holding a book that has a weight of 20N in her hand while sitting in a chair. She claims that the book must be attracting Earth with a force of 20 N. Her claim must be
Correct Answer
D. True due to Newtonâ€™s third law of motion
Explanation
The student's claim is true due to Newton's third law of motion. According to this law, for every action, there is an equal and opposite reaction. When the student holds the book, she exerts a force of 20N on the book. As a result, the book exerts an equal and opposite force of 20N on the student's hand. Similarly, according to Newton's third law, the book also exerts a force of 20N on the Earth, and the Earth exerts an equal and opposite force of 20N on the book. Therefore, the book is attracting the Earth with a force of 20N.
40.
A cart is rolling along a frictionless horizontal surface. Which of the following describes the motion of the cart as it continues to roll along the surface?
Correct Answer
B. The cart will continue to roll with constant speed
Explanation
The cart will continue to roll with constant speed because there is no friction acting on it to slow it down.
41.
Which object has the most inertia?
Correct Answer
D. A 10 kg tricycle at rest
Explanation
The object with the most inertia is the 10 kg tricycle at rest. Inertia is the resistance of an object to changes in its state of motion. It depends on the mass of the object. The tricycle has the highest mass among the given options, which means it has more inertia compared to the other objects. The fact that it is at rest does not affect its inertia because inertia is a property of an object regardless of its motion.
42.
Two students have a tug-of-war on a smooth gym floor. One student has a mass of 70 kg and is wearing socks but no shoes. The other student has a mass of 60 kg and is wearing athletic shoes. The student most likely to win will be
Correct Answer
C. The 60 kg student because he experiences greater frictional force with the floor
Explanation
The 60 kg student is most likely to win because he experiences greater frictional force with the floor. Frictional force depends on the normal force and the coefficient of friction. The normal force is equal to the weight of an object, which is the product of mass and acceleration due to gravity. Since both students are on the same smooth gym floor, the acceleration due to gravity is the same for both. However, the 60 kg student has a smaller mass, resulting in a smaller normal force and therefore a smaller frictional force. This allows the 60 kg student to have a greater advantage in pulling the other student.
43.
If the sum of all forces acting on a moving object is zero, the object will
Correct Answer
A. Continue moving with constant speed
Explanation
If the sum of all forces acting on a moving object is zero, it means that the forces are balanced. In this case, there is no net force acting on the object to change its motion. Therefore, the object will continue to move with a constant speed.
44.
What type of energy does the skater possess when he is at the greatest height on the track as shown in the picture above?
Correct Answer
B. Gravitational potential energy only
Explanation
Since the skater is temporarily at rest at the greatest height, he will only possess gravitational potential energy.
45.
What type of energy does the skater possess when he is moving pass the bottom of the track as shown in the picture above?
Correct Answer
C. Kinetic energy only
Explanation
The skater is at the reference for potential energy, so his PE is zero and since he is moving, he will possess kinetic energy.
46.
What type of energy does the skater possess as he is moving up the track as shown in the picture above?
Correct Answer
D. Gravitational potential energy and kinetic energy
Explanation
The skater possesses gravitational potential energy since he is at a height above the reference point and as he is moving, he also possesses kinetic energy.
47.
The picture above shows the skater at the starting point for his skate. Which position in the picture indicates the greatest height the skater can reach.
Correct Answer
C. Position C
Explanation
Skater's gravitational potential energy converts to kinetic energy as he moves towards the bottom of the track. The kinetic energy is then converted back to gravitational potential energy as he moves up on the right side of the track. So the greatest height he can reach must be the same height of his starting point.
48.
If the kinetic energy of an object is doubled, how many times will its velocity increase by?
Correct Answer
C. 4 times
Explanation
When the kinetic energy of an object is doubled, it means that the object has gained more energy and is moving faster. The kinetic energy of an object is directly proportional to the square of its velocity. Therefore, if the kinetic energy is doubled, the velocity will increase by the square root of 2, which is approximately 1.41 times. Hence, the velocity will increase approximately 4 times when the kinetic energy is doubled.
49.
A man is walking at 1 metre per second (m/s). He has a mass of 100 kilogram (Kg). How much kinetic energy does he have?
Correct Answer
D. 50 Joules.
Explanation
The kinetic energy of an object is given by the formula KE = 0.5 * mass * velocity^2. In this case, the man has a mass of 100 kg and is walking at a velocity of 1 m/s. Plugging these values into the formula, we get KE = 0.5 * 100 * 1^2 = 50 Joules. Therefore, the man has 50 Joules of kinetic energy.
50.
An object moves a distance of 10 metres due to a force pushing it to the right. How much work is done on the object in the direction, which is perpendicular to the direction off travel?
Correct Answer
C. No work is done.
Explanation
When a force is applied perpendicular to the direction of travel, no work is done on the object. Work is defined as the force applied in the direction of displacement. In this case, since the force is perpendicular to the direction of travel, there is no displacement in the direction of the force. Therefore, no work is done on the object.