Newton's laws of motion

A cube slides down the surface of a ramp at a constant velocity. What is the magnitude of the frictional force that acts on the cube due to the surface?

• The weight of the cube

• The component of weight of the cube parallel to the plane

• The component of weight of the cube perpendicular to the plane

• The component of the normal reaction at the surface parallel to the plane

A box is accelerated to the right across rough ground by a horizontal force F_a. The force of friction is F_f. The weight of the box is F_g and the normal reaction is F_n. Which is the free-body diagram for this situation?

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Two blocks of weight 5 N and 2 N are attached to two ropes, X and Y.

The blocks hang vertically. The mass of the ropes is negligible. What is the tension in X and the tension in Y?

• 7N, 7N

• 7N, 2N

• 5N, 2N

• 5N, 3N

A cart of mass 4.0 kg is being pulled with a force of 24 N. The cart accelerates at 3.0m s^–2. What is the net force on the cart?

• 6.0 N

• 8.0 N

• 12 N

• 24 N

Two boxes in contact are pushed along a floor with a force F. The boxes move at a constant speed. Box X has a mass m and box Y has a mass 2m..

What is the resultant force acting on Y?

• 0

• F/2

• F

• 2F

A constant force of 12 N is applied for 3.0 s to a body initially at rest. The final velocity of the body is 6.0m s^–1. What is the mass of the body?

• 1.5 kg

• 6.0 kg

• 24 kg

• 36 kg

A force F acts on a block at an angle θ with respect to a horizontal surface.

The block is moving with a constant velocity v along the surface. A resistive force acts on the block.

Which of the following correctly represents the forces acting on the block?

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An object falls vertically from rest. Air resistance acts on the object and it reaches a terminal speed. Which of the following is the distance–time graph for its motion?

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A block rests on a rough horizontal plane. A force P is applied to the block and the block moves to the right.

There is a coefficient of friction  giving rise to a frictional force F between the block and the plane. The force P is doubled. Will the coefficient and F be unchanged or greater?

• unchanged, unchanged

• unchanged, greater

• greater, greater

• greater, unchanged

A waiter carrying a tray is accelerating to the right as shown in the image.

What is the free-body diagram of the forces acting on the tray?

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