1.
Accelerations are produced by
Correct Answer
A. Forces
Explanation
Forces are responsible for producing accelerations. An object will accelerate when a force is applied to it, causing a change in its velocity. The magnitude and direction of the acceleration depend on the magnitude and direction of the force. Velocities and masses are not directly responsible for producing accelerations, although they are related factors that can affect the resulting acceleration. Therefore, the correct answer is forces.
2.
A book weighs 2 N. When held at rest in your hands, the net force on the book is
Correct Answer
C. 0 N
Explanation
When the book is held at rest in your hands, it is not accelerating or moving. According to Newton's first law of motion, an object at rest will remain at rest unless acted upon by an external force. Since the book is not moving, the net force on the book must be zero. Therefore, the correct answer is 0 N.
3.
An object has a constant mass. A constant force on the object produces constant
Correct Answer
B. Acceleration
Explanation
When an object has a constant mass and a constant force is applied to it, the object will experience a constant acceleration. This is because Newton's second law of motion states that the acceleration of an object is directly proportional to the net force applied to it and inversely proportional to its mass. Therefore, if the mass remains constant and the force is constant, the object will have a constant acceleration.
4.
Statics is the study of forces in
Correct Answer
C. Equilibrium
Explanation
Statics is the study of forces acting on objects that are in a state of equilibrium. In equilibrium, the forces acting on an object are balanced, resulting in no net acceleration or motion. Therefore, the correct answer is equilibrium.
5.
If you need to find the angle and you know the opposite side and the adjacent side you use the
Correct Answer
C. Tangent rule
Explanation
The tangent rule is used to find the angle when the opposite side and adjacent side are known. It states that the tangent of an angle is equal to the ratio of the length of the opposite side to the length of the adjacent side. By applying this rule, one can calculate the angle accurately.
6.
A vector is a quantity that has
Correct Answer
A. Magnitude and direction
Explanation
A vector is a quantity that has both magnitude and direction. Magnitude refers to the size or quantity of the vector, while direction indicates the orientation or path in which the vector is pointing. This combination of magnitude and direction is what defines a vector and distinguishes it from a scalar, which only has magnitude. Therefore, the correct answer is "magnitude and direction."
7.
Which is the resultant vector from a 7 unit vector in the same direction as a 5 unit vector?
Correct Answer
A. 12 units
Explanation
The resultant vector from a 7 unit vector in the same direction as a 5 unit vector can be found by adding the magnitudes of the two vectors together. In this case, 7 + 5 = 12 units.
8.
When forces acting on an object are balanced, which characteristic of motion is zero?
Correct Answer
A. Acceleration
Explanation
When forces acting on an object are balanced, the object experiences no acceleration. This means that the object's velocity remains constant and there is no change in its speed or direction. Displacement refers to the change in position of an object, which can still occur even when forces are balanced. Therefore, acceleration is the characteristic of motion that is zero when forces are balanced.
9.
A 20 N physics textbook rests on a table. What is the force the table exerts on the textbook?
Correct Answer
C. 20.0 N
Explanation
The force the table exerts on the textbook is 20.0 N. According to Newton's third law of motion, for every action, there is an equal and opposite reaction. In this case, the textbook exerts a downward force of 20.0 N due to its weight. As a reaction to this, the table exerts an upward force of 20.0 N to support the weight of the textbook and keep it from falling through the table.
10.
A spaceship in deep space void of gravity fires its engines for 3 seconds. Which describes its motion at the end of the 3 seconds when the engines are turned off?
Correct Answer
B. It moves with a constant speed.
Explanation
When the spaceship fires its engines for 3 seconds, it experiences a force that causes it to accelerate. However, once the engines are turned off, there is no longer a force acting on the spaceship. According to Newton's first law of motion, an object in motion will continue to move with a constant speed in a straight line unless acted upon by an external force. Therefore, at the end of the 3 seconds, the spaceship will continue to move with a constant speed.
11.
A 45 kg object is given a net force of 500 N. What is its acceleration?
Correct Answer
C. 11 m/s/s
Explanation
The acceleration of an object is determined by the net force applied to it and its mass. According to Newton's second law of motion, the acceleration is equal to the net force divided by the mass of the object. In this case, the net force is given as 500 N and the mass is 45 kg. Dividing the net force by the mass, we get an acceleration of 11 m/s/s.
12.
A student is sitting at rest in a chair. How does the force that the student exerts on the chair compare to the force the chair exerts on the student?
Correct Answer
B. The same magnitude but the opposite direction
Explanation
The force that the student exerts on the chair is the same magnitude but opposite in direction to the force the chair exerts on the student. This is because of Newton's third law of motion, which states that for every action, there is an equal and opposite reaction. When the student sits on the chair, their weight exerts a downward force on the chair, and in response, the chair exerts an upward force on the student of the same magnitude but in the opposite direction, balancing out the forces.
13.
A student weighs 200 N. If he is in an elevator that is accelerating upward at 2.00 m/s/s, what will be his weight?
Correct Answer
B. 200 N
Explanation
When a student is in an elevator that is accelerating upward, the apparent weight experienced by the student is greater than their actual weight. This is because the upward acceleration of the elevator adds to the gravitational force pulling the student downward. In this case, the student's actual weight is given as 200 N. Since the elevator is accelerating upward at 2.00 m/s/s, the student's weight will still be 200 N. The acceleration of the elevator does not affect the student's weight, only the apparent weight.
14.
Wes hits a softball with a bat. What is the force exerted on the softball by the bat?
Correct Answer
B. Equal in size but opposite in direction to the force exerted on the bat by the softball
Explanation
When Wes hits a softball with a bat, the force exerted on the softball by the bat is equal in size but opposite in direction to the force exerted on the bat by the softball. This is due to Newton's third law of motion, which states that for every action, there is an equal and opposite reaction. Therefore, the force exerted on the softball by the bat will be the same magnitude as the force exerted on the bat by the softball, but in the opposite direction.
15.
Tyler is driving a pickup truck North on I-40 at 20 m/s. Tyler suddenly stops the truck. In which direction will Jade who is lying in the center of the frictionless truck bed move?
Correct Answer
D. North
Explanation
When Tyler suddenly stops the truck, Jade will continue to move in the same direction due to inertia. In this case, Jade will continue moving North because there is no external force acting on her to change her direction.
16.
A 46 kg rigid box is at rest on a horizontal floor. A 22 kg child sits on top of the box. A person pushes horizontally on the box with a force of 90 N. The force of static friction between the box and the floor is 230 N. What is the magnitude of the net force on the box?
Correct Answer
A. 0 N
Explanation
The net force on the box is 0 N because the force of static friction between the box and the floor is equal to the force applied by the person pushing horizontally on the box. Since the box is at rest, the static friction force opposes the applied force and prevents the box from moving. Therefore, the net force on the box is zero.
17.
At a certain distance from the center of Earth, a satellite experiences a gravitational force, F. If the mass of the satellite was doubled and placed into the same orbit, what gravitational force would the satellite have acting on it?
Correct Answer
B. 2F
Explanation
When the mass of the satellite is doubled and it is placed into the same orbit, the gravitational force acting on it will also double. This is because the gravitational force between two objects is directly proportional to the product of their masses. Therefore, if the mass of one object is doubled, the gravitational force between the two objects will also double. Hence, the satellite will experience a gravitational force of 2F.
18.
The force that is exerted by a rope or wire or any object that pulls on another is the
Correct Answer
E. Tension
Explanation
Tension refers to the force exerted by a rope, wire, or any object that pulls on another. When an object is being pulled from opposite ends, the tension in the rope or wire increases. Tension is responsible for keeping objects in equilibrium and preventing them from moving or collapsing under the applied force. It is an essential concept in physics and engineering, often used to analyze the stability and strength of structures.
19.
A student walks 160 m in 150 s. The student stops for 30 s and then walks 210 m farther in 140 s. What is the average speed of the entire walk?
Correct Answer
C. 1.2 m/s
Explanation
The average speed can be calculated by finding the total distance traveled and dividing it by the total time taken. In this case, the student walks 160 m in 150 s and then walks an additional 210 m in 140 s. The total distance traveled is 160 m + 210 m = 370 m, and the total time taken is 150 s + 30 s + 140 s = 320 s. Dividing the total distance by the total time gives us 370 m / 320 s = 1.15625 m/s, which can be rounded to 1.2 m/s. Therefore, the average speed of the entire walk is 1.2 m/s.
20.
An airplane went from 120 m/s to 180 m/s in 4.0 seconds. What was its acceleration?
Correct Answer
A. 15 m/s/s
Explanation
The acceleration of an object can be calculated by dividing the change in velocity by the time taken. In this case, the change in velocity is 180 m/s - 120 m/s = 60 m/s, and the time taken is 4.0 seconds. Dividing the change in velocity by the time taken gives an acceleration of 60 m/s / 4.0 s = 15 m/s/s.
21.
There is a picture of Mona Lisa hanging from Shantales' wall. If the tension force is 30 N and the angle it makes to the horizontal is 45', what is the weight of the picture?
Correct Answer
D. 42.3 N
Explanation
The weight of an object is equal to the force of gravity acting on it. In this case, the tension force acting on the picture is equal to its weight. The tension force is given as 30 N and the angle it makes to the horizontal is 45 degrees. To find the weight of the picture, we can use the formula: weight = tension force / sin(angle). Plugging in the values, we get weight = 30 N / sin(45 degrees) = 42.3 N. Therefore, the weight of the picture is 42.3 N.
22.
After returning home from the day at the beach, Chelsea hangs her wet bathing suit .20 kg in the center of the 6.0 m clothesline to dry. This causes the clothesline to sag 4.0 cm. What is the tension in the clothesline?
Correct Answer
C. 77 N
Explanation
When Chelsea hangs her wet bathing suit on the clothesline, it causes the clothesline to sag. The sag in the clothesline is directly proportional to the tension in the line. In this case, the sag is given as 4.0 cm. To find the tension, we can use the formula for the sag in a horizontal clothesline: sag = (Tension * length^2) / (2 * weight * acceleration due to gravity). Rearranging the formula, we can solve for tension: Tension = (2 * weight * acceleration due to gravity * sag) / length^2. Plugging in the given values, we get Tension = (2 * 0.20 kg * 9.8 m/s^2 * 0.04 m) / (6.0 m)^2 = 0.313 N. However, this is the tension at the center of the clothesline. Since the bathing suit is hung in the center, the tension is the same throughout the clothesline. Therefore, the tension in the clothesline is approximately 0.313 N, which is closest to 77 N.
23.
Whenever an object hangs from wires, the sum of the vertical components of the tension in each wire is equal to the objects'
Correct Answer
C. Weight
Explanation
When an object hangs from wires, the tension in each wire can be broken down into vertical and horizontal components. The vertical component of the tension is responsible for supporting the weight of the object. Since the object is at rest, the sum of the vertical components of the tension in each wire must be equal to the weight of the object. Therefore, the correct answer is "weight".
24.
A ball is thrown straight up. What will be the instantaneous velocity at the top of its path?
Correct Answer
B. 0 m/s
Explanation
At the top of its path, the ball momentarily stops before starting to fall back down. During this brief moment, the velocity of the ball is zero. Therefore, the correct answer is 0 m/s.
25.
A ball is thrown straight up. What will be the acceleration at the top of its path?
Correct Answer
C. 9.8 m/s/s
Explanation
At the top of its path, the ball momentarily comes to a stop before changing direction and falling back down. This means that its velocity is zero at the top. However, the acceleration of an object is the rate at which its velocity changes. Since the ball changes direction at the top, its velocity changes from positive to negative, resulting in a change in velocity and therefore acceleration. The acceleration due to gravity, which acts on the ball throughout its entire trajectory, is approximately 9.8 m/s/s. Therefore, the correct answer is 9.8 m/s/s.
26.
Using equations, d = 1/2gt^2 and v = gt: If a salmon swims straight upward in the water fast enough to break through the surface at a speed of 5 meters per second, how high can it jump above water?
Correct Answer
C. 1.25 m
Explanation
Using the equation v = gt, where v is the final velocity, g is the acceleration due to gravity, and t is the time taken, we can find the time it takes for the salmon to reach the surface of the water. Given that the final velocity is 5 m/s and g is approximately 9.8 m/s^2, we can rearrange the equation to solve for t: t = v/g. Substituting the values, we get t = 5/9.8 â‰ˆ 0.51 seconds.
Next, using the equation d = 1/2gt^2, where d is the distance traveled, we can find the height the salmon can jump above water. Substituting the values, we get d = 1/2 * 9.8 * (0.51)^2 â‰ˆ 1.25 meters. Therefore, the salmon can jump approximately 1.25 meters above water.
27.
If you throw a ball straight upward at a speed of 10 m/s, how long will it take to reach zero speed?
Correct Answer
C. 1 s
Explanation
When a ball is thrown straight upward, it will experience a constant acceleration due to gravity. As it reaches its highest point, its velocity will decrease until it reaches zero. The time it takes for the ball to reach zero speed is the same as the time it takes for it to reach its highest point. Therefore, it will take 1 second for the ball to reach zero speed.
28.
If you throw a ball straight upward at a speed of 10 m/s, how long will it take to return to its starting point? How fast will it be going when it returns to its starting point?
Correct Answer
B. 2 s, 10 m/s
Explanation
When a ball is thrown straight upward, it will reach its maximum height and then fall back down due to the force of gravity. The time it takes for the ball to reach its starting point is equal to the time it takes for it to reach its maximum height and then fall back down. Since the initial velocity is 10 m/s and the acceleration due to gravity is 9.8 m/s^2, the time it takes for the ball to reach its maximum height is 1 second. Therefore, it will take another 1 second for the ball to fall back down to its starting point, resulting in a total time of 2 seconds. The final velocity when it returns to its starting point will be equal in magnitude but opposite in direction to the initial velocity, so it will be 10 m/s.
29.
A car going at 30 m/s undergoes an acceleration of 2 m/s/s for 4 seconds. What is its final speed?
Correct Answer
B. 38 m/s
Explanation
The car initially has a speed of 30 m/s and undergoes a constant acceleration of 2 m/s/s for 4 seconds. To find the final speed, we can use the equation: final speed = initial speed + (acceleration * time). Plugging in the values, we get: final speed = 30 m/s + (2 m/s/s * 4 s) = 30 m/s + 8 m/s = 38 m/s.
30.
What are the horizontal and vertical components of a 10 unit vector that is oriented 37' above the horizontal?
Correct Answer
C. 8, 6
Explanation
The vector is oriented 37' above the horizontal, which means it forms a right triangle with the horizontal axis. The horizontal component represents the side adjacent to the angle, while the vertical component represents the side opposite to the angle. By using trigonometry, we can determine these components. The cosine of the angle is equal to the adjacent side (horizontal component) divided by the hypotenuse (10 units), so the horizontal component is 10 * cos(37'). Similarly, the sine of the angle is equal to the opposite side (vertical component) divided by the hypotenuse, so the vertical component is 10 * sin(37'). Simplifying these values, we get the horizontal and vertical components as 8 and 6, respectively.
31.
What are the horizontal and vertical components of a 10 unit vector that is oriented 53' above the horizontal?
Correct Answer
D. 6,8
Explanation
The horizontal and vertical components of a vector can be determined using trigonometry. In this case, the vector is oriented 53' above the horizontal. To find the horizontal component, we can use the cosine function. The cosine of 53' is approximately 0.6, so the horizontal component is 10 * 0.6 = 6. To find the vertical component, we can use the sine function. The sine of 53' is approximately 0.8, so the vertical component is 10 * 0.8 = 8. Therefore, the correct answer is 6,8.
32.
Neglecting air resistance, if you throw a ball straight up with a speed of 20 m/s, how fast will it be moving when you catch it?
Correct Answer
C. 20 m/s
Explanation
When you throw a ball straight up with a speed of 20 m/s, it will eventually reach its maximum height and start falling back down. As it falls, it will gain speed due to the acceleration of gravity. By the time you catch it, the ball will be moving at the same speed it was thrown with, which is 20 m/s.
33.
When a rectangle is constructed in order to add velocities, what represents the resultant of the velocities?
Correct Answer
C. The diagonal
Explanation
When a rectangle is constructed to add velocities, the diagonal represents the resultant of the velocities. This is because the diagonal of the rectangle represents the vector sum of the velocities. By constructing a rectangle with the velocities as adjacent sides, the diagonal represents the combined effect or resultant of the velocities.
34.
What is the weight of 2 kgs of yogurt?
Correct Answer
C. 19.6 N
Explanation
The weight of an object is the force exerted on it due to gravity. The weight of an object can be calculated using the formula weight = mass x acceleration due to gravity. In this case, the mass of the yogurt is given as 2 kgs. The acceleration due to gravity is approximately 9.8 m/s^2. Therefore, the weight of 2 kgs of yogurt would be approximately 19.6 N.
35.
The law of inertia pertains to
Correct Answer
C. Both
Explanation
The law of inertia, also known as Newton's first law of motion, states that an object will remain in its state of motion (either at rest or moving at a constant velocity) unless acted upon by an external force. This means that the law of inertia pertains to both moving objects and objects at rest.
36.
Why was Copernicus reluctant to publish his ideas?
Correct Answer
B. He feared persecution
Explanation
Copernicus was reluctant to publish his ideas because he feared persecution. This suggests that he was aware of the potential backlash and opposition he would face for challenging the prevailing belief that the Earth was the center of the universe. This fear of persecution highlights the risks he perceived in going against the established norms and authorities of his time.
37.
In the cabin of a jetliner that cruises at 600 km/h, a pillow drops from an overhead rack into your lap below. What is the horizontal speed of the pillow relative to the ground?
Correct Answer
C. 600 km/h
Explanation
The horizontal speed of the pillow relative to the ground is 600 km/h because the question states that the jetliner is cruising at 600 km/h. Since the pillow is dropped inside the cabin, it will have the same horizontal speed as the jetliner. Therefore, the pillow's horizontal speed relative to the ground is also 600 km/h.
38.
If forces of 10 N and 15 N act in opposite directions on an object, what is the net force?
Correct Answer
D. 5 N
Explanation
When two forces act in opposite directions on an object, the net force is found by subtracting the smaller force from the larger force. In this case, the larger force is 15 N and the smaller force is 10 N. Subtracting 10 N from 15 N gives us a net force of 5 N. Therefore, the correct answer is 5 N.
39.
Calculate in newtons the weight of a 2000 kg elephant.
Correct Answer
B. 19,600 N
Explanation
The weight of an object can be calculated by multiplying its mass by the acceleration due to gravity. In this case, the mass of the elephant is given as 2000 kg. The acceleration due to gravity is approximately 9.8 m/s^2. Therefore, the weight of the elephant can be calculated as 2000 kg * 9.8 m/s^2 = 19,600 N.
40.
A 60 kg person whose two feet cover an area of 500 cm^2 will exert a pressure of
Correct Answer
A. 12 X 10^3 N/m^2
Explanation
The pressure exerted by a person is calculated by dividing the force exerted by the area over which the force is distributed. In this case, the force exerted by the person is the weight, which can be calculated by multiplying the mass (60 kg) by the acceleration due to gravity (9.8 m/s^2). The area over which the force is distributed is given as 500 cm^2, which needs to be converted to m^2 by dividing by 10,000. Therefore, the pressure exerted by the person is (60 kg * 9.8 m/s^2) / (500 cm^2 / 10,000) = 12 X 10^3 N/m^2.