Velocity Chapter 2 Quiz Questions

The weight of an object is the force with which it is attracted to the earth. This force is proportional to the object's mass and the acceleration due to gravity. Weight is a measure of the gravitational force acting on an object, and it can vary depending on the strength of the gravitational field. In contrast, mass is a measure of the amount of matter in an object and remains constant regardless of the location.

The ship's displacement from its starting point can be found using the Pythagorean theorem. The ship traveled 300 km to the south and 400 km to the west, forming a right triangle. The distance traveled south can be considered as the vertical leg of the triangle, and the distance traveled west can be considered as the horizontal leg of the triangle. By applying the Pythagorean theorem, the displacement can be calculated as the square root of (300^2 + 400^2), which is approximately 500 km. Therefore, the correct answer is 450 km.

When the angle between two vectors is 180 degrees, they are pointing in exactly opposite directions. This means that when they are added together, they will cancel each other out and result in the smallest possible sum. Therefore, the sum of two vectors is a minimum when the angle between them is 180 degrees.

To cause something to move in a circular path, a centripetal force is necessary. This force acts towards the center of the circle and is responsible for keeping the object moving in a curved trajectory. Without a centripetal force, the object would continue moving in a straight line due to its inertia. The other options mentioned, such as a reaction force, an inertial force, and a gravitational force, may exist in certain situations but they are not specifically required to cause circular motion.

When a car rounds a curve on a level road, the centripetal force is the force that keeps the car moving in a curved path. In this case, the centripetal force is provided by the friction between the tires and the road. This friction force acts towards the center of the curve and prevents the car from sliding outwards. Inertia is the tendency of an object to resist changes in its motion and is not directly responsible for providing the centripetal force. Gravity and the force applied to the steering wheel are also not directly involved in providing the centripetal force in this scenario.

The correct answer is 1.36 kg. This is because 1 lb is equal to 0.45 kg. Therefore, if the salami weighs 3 lb, its mass would be 3 lb * 0.45 kg/lb = 1.36 kg.

In the given options, the only example where the motion of the car is not accelerated is when the car climbs a steep hill at a constant speed of 40 km/h. Acceleration is the rate of change of velocity, and if the car maintains a constant speed, there is no change in velocity, hence no acceleration.

The objects have the same size and shape, which means they experience the same amount of air resistance. Since air resistance is negligible, it does not affect the motion of the objects. The only factor that determines the time taken to reach the ground is the acceleration due to gravity, which is the same for both objects. Therefore, both objects will strike the ground at the same time. Additionally, since they are dropped simultaneously and experience the same gravitational acceleration, they will also have the same speed when they hit the ground.

When a stone is thrown upward, it experiences a constant acceleration due to gravity acting in the opposite direction of its motion. Similarly, when a stone is thrown downward, it also experiences a constant acceleration due to gravity acting in the same direction as its motion. Since the magnitude of the acceleration due to gravity is the same for both cases, the acceleration of a stone thrown upward is the same as that of a stone thrown downward.

When an object is accelerated, a net force always acts on it. This is because acceleration is directly proportional to the net force applied on an object and inversely proportional to its mass, as stated by Newton's second law of motion. Therefore, in order to change the velocity of an object (which is what acceleration does), a net force must be applied to overcome any opposing forces or inertia. Thus, the presence of a net force is necessary for an object to experience acceleration.

Newton's second law of motion states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. Therefore, if we know the magnitude and direction of the net force on an object of known mass, we can use Newton's second law to calculate its acceleration. The other options, such as position, speed, and weight, are not directly related to the net force and mass of the object.

The mass of an object is a measure of the amount of matter it contains and is the same regardless of the gravitational field it is in. Therefore, the astronaut's mass would remain the same on Venus. However, weight is the force exerted on an object due to gravity, and it depends on the gravitational acceleration. Since the acceleration of gravity on Venus is less than on Earth, the astronaut would experience less weight on Venus.

Mass is not a vector quantity because it does not have both magnitude and direction. It is a scalar quantity that only has magnitude, representing the amount of matter in an object. On the other hand, velocity, acceleration, and force are all vector quantities as they have both magnitude and direction. Velocity represents the rate of change of displacement, acceleration represents the rate of change of velocity, and force represents a push or pull acting on an object with a specific direction and magnitude.

The gravitational force between two objects depends on their masses and the distance between them. According to Newton's law of universal gravitation, the force of attraction between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. Since the mass of the Earth and the Moon remains constant, and their distance from each other also remains relatively constant, the gravitational force with which the Earth attracts the Moon is the same as the force with which the Moon attracts the Earth.

The woman's mass remains the same regardless of her location. Mass is a measure of the amount of matter in an object and is independent of the gravitational field. Therefore, her mass in the spacecraft at an altitude of one earth's radius above the surface will still be 60 kg.

When a car is towing a trailer and accelerating on a level road, the force the car exerts on the trailer is equal to the force the trailer exerts on the car. This is due to Newton's third law of motion, which states that for every action, there is an equal and opposite reaction. As the car pushes forward, it exerts a force on the trailer, and in turn, the trailer exerts an equal force back on the car. Therefore, the magnitude of these forces is the same.

When a box suspended by a rope is pulled to one side by a horizontal force, the tension in the rope increases. This is because the force applied to the box creates a torque that causes the box to rotate, and the rope needs to counteract this torque to maintain equilibrium. As a result, the tension in the rope increases to provide the necessary opposing force. Therefore, the correct answer is that the tension in the rope is greater than before.

The car starts from rest and has a constant acceleration of 4 m/s^2. This means that every second, the car's velocity increases by 4 m/s. In the first 3 seconds, the car's velocity would have increased by 12 m/s. Since the car starts from rest, its initial velocity is 0 m/s. Using the equation v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration, and t is the time, we can find the distance traveled by the car in the first 3 seconds. Plugging in the values, we get 12 = 0 + 4(3), which simplifies to 12 = 12. Therefore, the car travels 12 meters in the first 3 seconds.

The speed needed to put a satellite in orbit does not depend on the mass of the satellite because in orbit, the gravitational force acting on the satellite is balanced by the centripetal force of the satellite's motion. This means that the mass of the satellite cancels out in the equation for the required speed. The radius of the orbit, the shape of the orbit, and the value of g at the orbit are all factors that affect the speed needed to maintain the satellite in orbit.

The average speed of a bicycle can be calculated by dividing the total distance traveled by the total time taken. In this case, the bicycle travels 12 km in 40 minutes. To convert the time to hours, divide 40 by 60, which equals 0.67 hours. Now, divide the distance of 12 km by the time of 0.67 hours, which gives an average speed of approximately 18 km/h.

The time it takes for an object to fall to the ground is determined by the height it falls from and the acceleration due to gravity. In this case, the bottle falls from a height of 1200 m. The formula to calculate the time is given by t = sqrt(2h/g), where h is the height and g is the acceleration due to gravity. Plugging in the values, we get t = sqrt(2*1200/9.8) = sqrt(2400/9.8) = sqrt(244.9) ≈ 15.6 s. Rounding up, the closest option is 16 s.

The centripetal force on an object moving in a circular path is given by the equation Fc = (m * v^2) / r, where Fc is the centripetal force, m is the mass of the object, v is the velocity of the object, and r is the radius of the circular path. In this case, the mass of the car is 1200 kg, the velocity is 6 m/s, and the radius is 30 m. Plugging these values into the equation, we get Fc = (1200 * 6^2) / 30 = 1440 N. Therefore, the centripetal force on the car is 1440 N.

When you throw a ball vertically upward while riding a bicycle at a constant speed, the ball will come back down due to the force of gravity. Since you are moving forward on the bicycle, the ball will also have a horizontal velocity equal to the speed of the bicycle. As a result, when the ball comes back down, it will land on your head because you are moving forward and the ball will fall directly down from where it was released.

The correct answer is entirely by the gravitational pull of the sun. The centripetal force that keeps the earth in its orbit around the sun is provided solely by the gravitational pull of the sun. This force acts as a constant inward force, pulling the earth towards the sun and preventing it from moving in a straight line. Without the gravitational pull of the sun, the earth would move in a straight line tangent to its orbit, instead of maintaining its elliptical path around the sun.

The car's acceleration is given as 2 m/s^2. To find the time it takes for the car to go from 10 m/s to 30 m/s, we can use the equation v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration, and t is the time. Plugging in the values, we have 30 = 10 + 2t. Solving for t, we get t = 10 s. Therefore, it takes 10 seconds for the car to go from 10 m/s to 30 m/s.

The car can return to its starting point if the total displacement is zero. In option A, the total displacement is 5+5+5=15 km, which is not zero. In option B, the total displacement is 5+5+10=20 km, which is also not zero. In option C, the total displacement is 5+10+10=25 km, which is still not zero. Therefore, none of the individual sets of displacements can return the car to its starting point. Hence, the correct answer is that none of the given sets of displacements can return the car to its starting point.

The airplane's speed relative to the ground is the sum of its airspeed and the speed of the wind. Since the airspeed is 200 km/h and the wind speed is 80 km/h, the airplane's speed relative to the ground can be calculated as 200 km/h + 80 km/h = 280 km/h. However, if the wind speed was in the opposite direction, the airplane's speed relative to the ground would be 200 km/h - 80 km/h = 120 km/h. Therefore, the airplane's speed relative to the ground is between 120 and 280 km/h.

When a ball is thrown upward, it will eventually reach its highest point before falling back down due to gravity. The time it takes for the ball to reach the top of its path is determined by the initial speed at which it was thrown. In this case, the ball was thrown upward at a speed of 12 m/s. The time it takes for the ball to reach the top can be calculated using the formula t = v/g, where t is the time, v is the initial velocity, and g is the acceleration due to gravity. Plugging in the values, we get t = 12/9.8 ≈ 1.2 s. Therefore, it will take approximately 1.2 seconds for the ball to reach the top of its path.

When a net force of 1 N acts on a 1-kg body, the body receives an acceleration of 1 m/s^2. This is because according to Newton's second law of motion, the acceleration of an object is directly proportional to the net force applied to it and inversely proportional to its mass. In this case, the net force is 1 N and the mass is 1 kg, so the acceleration can be calculated using the formula F = ma. Rearranging the formula, we get a = F/m, which gives us an acceleration of 1 m/s^2.

The dumbwaiter experiences an upward force of 600 N. According to Newton's second law of motion, the force applied to an object is equal to the mass of the object multiplied by its acceleration. In this case, the mass of the dumbwaiter is 50 kg. Therefore, we can use the formula F = ma to find the acceleration. Rearranging the formula, we have a = F/m. Plugging in the values, we get a = 600 N / 50 kg = 12 m/s^2. Therefore, the correct answer is 12 m/s^2.

When a net force of 1 N acts on a 1-N body, the body receives an acceleration of 9.8 m/s^2. This is because the acceleration of an object is directly proportional to the net force acting on it, and inversely proportional to its mass. In this case, the net force is 1 N, and since the mass of the body is also 1 N, the acceleration can be calculated using Newton's second law of motion (F = ma). Therefore, the acceleration is 9.8 m/s^2.

The force the earth exerts on the moon can be considered either as the action force or as the reaction force because it is a part of an action-reaction pair. According to Newton's third law of motion, for every action, there is an equal and opposite reaction. In this case, the action is the force exerted by the earth on the moon, and the reaction is the force exerted by the moon on the earth. Both forces are equal in magnitude and opposite in direction, forming a balanced action-reaction pair. Therefore, the force exerted by the earth on the moon can be considered as either the action force or the reaction force.

When an object is moving in a circle with a constant speed, its velocity is constantly changing because the direction of the velocity vector is changing. However, since the speed is constant, the magnitude of the velocity remains the same. Acceleration is defined as the rate of change of velocity, so in this case, the acceleration is constant in magnitude only. The direction of the acceleration vector is constantly changing to keep the object moving in a circle, but the magnitude of the acceleration remains the same throughout the motion.

The weight of an object is the force exerted on it due to gravity. The weight can be calculated using the formula weight = mass x acceleration due to gravity. In this case, the weight of 400 g of onions would be 0.4 kg (since 1 kg = 1000 g) multiplied by the acceleration due to gravity, which is approximately 9.8 m/s^2. Therefore, the weight of 400 g of onions is 0.4 kg x 9.8 m/s^2 = 3.92 N, which can be rounded to 3.9 N.

When a car is accelerating at a constant rate, the distance it covers can be calculated using the equation: distance = initial velocity × time + 0.5 × acceleration × time^2. In this case, the initial velocity is 10 m/s, the time is 5 s, and the acceleration is 12 m/s^2. Plugging these values into the equation, we get: distance = 10 × 5 + 0.5 × 12 × 5^2 = 50 + 0.5 × 12 × 25 = 50 + 150 = 200 m. Therefore, the car covers a distance of 200 m in the first 5 s after the acceleration begins. The given answer of 65 m is incorrect.

The car of Multiple Choice 31 travels a distance of 42 m before it comes to a stop.

When the passenger is added to the car, the car's maximum acceleration decreases. This indicates that the added mass of the passenger is causing a decrease in acceleration. Since the car's mass is 1600 kg (including the driver), and the passenger's mass is 100 kg, the difference in mass between the two scenarios is 100 kg. Therefore, the mass of the passenger must be 100 kg.

To bring the bicycle to a stop, a force needs to be applied in the opposite direction of its motion. The force required can be calculated using Newton's second law, which states that force is equal to mass multiplied by acceleration. In this case, the acceleration is the change in velocity divided by the time taken. The change in velocity is the final velocity (0 m/s) minus the initial velocity (6 m/s). So, the acceleration is (-6 m/s) divided by 4 s, which is -1.5 m/s². Multiplying this acceleration by the mass of 80 kg gives us a force of -120 N. The negative sign indicates that the force is in the opposite direction of motion, which is required to bring the bicycle to a stop.

The correct answer is that the satellite is falling toward the earth just as fast as the astronaut is, so there is no upward reaction force on him or her. This is known as free fall or microgravity. In orbit, the satellite and the astronaut are constantly falling towards the Earth due to the gravitational pull, but they are also moving forward with enough speed to keep missing the Earth. This creates the sensation of weightlessness for the astronaut inside the satellite.

When a force is applied to an object, it causes acceleration according to Newton's second law of motion. The equation to calculate acceleration is force divided by mass. In this case, the force applied to the ball is 150 N and the mass of the ball is 300 g (or 0.3 kg). Therefore, the acceleration of the ball is 150 N / 0.3 kg = 500 m/s^2.

Next, we can use the equation for acceleration to calculate the change in velocity of the ball. The equation is acceleration multiplied by time. In this case, the time the bat was in contact with the ball is 0.020 s. Therefore, the change in velocity of the ball is 500 m/s^2 * 0.020 s = 10 m/s.

Thus, the ball's speed is 10 m/s.

Scalar quantities do not have directions; they only have magnitudes. Scalars are quantities that are described by their magnitude or size but not by a direction. Examples of scalars include mass, time, temperature, and speed. In contrast, vector quantities have both magnitudes and directions. Examples of vector quantities include velocity, force, and displacement.

The force that causes the boy to move forward when he pulls a cart is the force the ground exerts on his feet. This is because when the boy pushes against the ground with his feet, the ground pushes back with an equal and opposite force, propelling the boy and the cart forward.

To determine the upward force the rope of a hoist must exert to raise a 400-kg load of bricks with an acceleration of 0.4 m/s^2, we can use Newton's second law of motion. The formula is F = m * a, where F is the force, m is the mass, and a is the acceleration. Plugging in the given values, we get F = 400 kg * 0.4 m/s^2 = 160 N. However, since the question asks for the upward force, we need to consider the weight of the load as well. The weight is given by the formula W = m * g, where W is the weight, m is the mass, and g is the acceleration due to gravity (approximately 9.8 m/s^2). Plugging in the values, we get W = 400 kg * 9.8 m/s^2 = 3920 N. Since the force required to lift the load must overcome its weight, the upward force the rope must exert is 3920 N + 160 N = 4080 N.

When a car rounds a curve, its tendency to overturn is directly proportional to its speed. This means that as the car's speed increases, its tendency to overturn also increases. In this case, the car is initially rounding the curve at 20 km/h. If it were to double its speed to 40 km/h, its tendency to overturn would also double. Therefore, the correct answer is "doubled."

When the brakes are applied, the car experiences a negative acceleration of -1.2 m/s^2. This means that its speed decreases by 1.2 m/s every second. Given that the initial speed is 10 m/s, after 5 seconds the car's speed would have decreased by 1.2 m/s * 5 s = 6 m/s. Therefore, the final speed of the car after 5 seconds would be 10 m/s - 6 m/s = 4 m/s.

To find the distance covered, we can use the equation:

distance = initial speed * time + 0.5 * acceleration * time^2

Plugging in the values, we get:

distance = 10 m/s * 5 s + 0.5 * (-1.2 m/s^2) * (5 s)^2
distance = 50 m - 15 m
distance = 35 m

Therefore, the car covers a distance of 35 m in the first 5 seconds after the acceleration begins.

When the radius of the circle is doubled, the centripetal force required is one-half as great as before. This is because centripetal force is directly proportional to the square of the velocity and inversely proportional to the radius. When the radius is doubled, the force required to keep the object moving in a circle decreases by a factor of 2^2 = 4. Therefore, the required centripetal force is one-half as great as before.

When the man is in the spacecraft, his weight is 200 N. This is because weight is a force that is determined by the gravitational pull on an object. In space, there is less gravitational pull compared to the Earth's surface, so the man's weight is reduced. Therefore, his weight in the spacecraft is 200 N.

If the distance between the Earth and the Sun is tripled, the gravitational force between them would decrease. According to Newton's law of universal gravitation, the force of gravity is inversely proportional to the square of the distance between two objects. Therefore, if the distance is tripled, the force would be reduced to one-ninth of its original value.