4 Forces 2020 JnN

The diagram shows three forces acting on an object.

What is the value of the resultant force acting on the object?

• 2 N

• 10 N

• 14 N

• 16 N

The diagram shows a car moving along a road.

The force due to the engine is 1500 N and the total drag force is 200 N.

What is the motion of the car?

• constant speed

• decreasing speed

• increasing speed

• reversing

A car travels along a horizontal road at constant speed.

Three horizontal forces act on the car.

The diagram shows two of these forces.

What is the size and the direction of the third horizontal force acting on the car?

• 1200 N backwards

• 1200 N forwards

• 1800 N backwards

• 1800 N forwards

A ball falls from rest through the air towards the ground.

The diagram shows two forces acting on the ball.

As the ball falls, the air resistance increases.

Which statement is correct?

• The acceleration of the ball decreases.

• The acceleration of the ball increases.

• The speed of the ball decreases.

• The gravitational force on the ball decreases.

A compressed spring projects a ball horizontally in a vacuum chamber.

On the Earth, the ball reaches the chamber floor 4.0 m in front of the spring.

An identical experiment is done on the Moon.

The gravitational field strength is lower on the Moon than on the Earth.

The experimental results on the Moon are compared with those on the Earth.

Which statement is correct?

• The horizontal speed is greater on the Moon and the ball hits the floor 4.0 m in front of the spring.

• The horizontal speed is greater on the Moon and the ball hits the floor more than 4.0 m in front of the spring.

• The horizontal speed is the same on the Moon and the ball hits the floor 4.0 m in front of the spring.

• The horizontal speed is the same on the Moon and the ball hits the floor more than 4.0 m in front of the spring.

A car is driven round a bend in the road at a constant speed. What is the direction of the resultant force on the car when it is going round the bend?

• parallel to the motion and in the same direction as the motion

• parallel to the motion and in the opposite direction to the motion

• perpendicular to the motion and towards the inside of the bend

• perpendicular to the motion and towards the outside of the bend

An air pistol fires a pellet forwards. What is the motion of the air pistol?

• The air pistol moves backwards with speed greater than the pellet.

• The air pistol moves backwards with speed less than the pellet.

• The air pistol moves forward with speed greater than the pellet.

• The air pistol moves forward with speed less than the pellet.

A sledge is pulled in a straight line by dogs, as shown.

The dogs produce a total horizontal driving force of 600 N.

The frictional force between the sledge and the surface is 150 N and the air resistance on the sledge is 450 N.

What is the resultant force acting on the sledge?

• 0 N

• 300 N

• 900 N

• 1200 N

Student P uses a force of 35 N to push a box 3.0 m across the floor.

Student Q uses a force of 22 N to push another box 1.8 m across the floor.

Which statement gives a full explanation why student P uses more energy than student Q?

• Student P pushes his box a greater distance than student Q.

• Student P pushes his box a greater distance and uses a bigger force than student Q.

• Student P uses a bigger force than student Q.

• Student P pushes a heavier box than student Q.

The diagram shows an extension–load graph for a spring.

An empty can of weight 3.0 N is suspended from the spring. Liquid is poured into the can until the extension is 8.0 cm.

What is the weight of the liquid?

• 4.0 N

• 10.0 N

• 13.0 N

• 16.0 N