Gr 10_Assignment D (Forces)

A boat is travelling at a steady speed in a straight line across the surface of a lake.

Which statement about the boat is correct?

• The resultant force on the boat is in the direction of motion.

• The resultant force on the boat is in the opposite direction to its motion.

• The resultant force on the boat is vertically downwards.

• The resultant force on the boat is zero.

An object always has mass but does not always have weight. What must be present and acting on the mass for it to have weight?

• A gravitational field

• A set of scales

• Displaced water

• Friction due to air resistance

A mass of 4.0 kg rests on the surface of a planet. On this planet, g = 20 N/kg. What is the weight of the object?

• 0.40 N

• 0.80 N

• 80 N

• 120 N

A cart has a mass of 10 kg. A boy pushes on the cart horizontally with a force of 50 N. The cart accelerates at 0.50 m/s². What is the frictional force acting on the cart?

• 5.0 N

• 20 N

• 30 N

• 45 N

The extension–load graph for a spring is shown. The unstretched length of the spring is 17.0 cm. When an object is suspended from the spring, the length of the spring is 19.2 cm. What is the weight of the object?

• 1.4 N

• 1.6 N

• 2.6 N

• 3.0 N

A spring is stretched by hanging a piece of metal from it. Which name is given to the force that stretches the spring?

• Friction

• Mass

• Pressure

• Weight

A body of mass m has a weight W in a location where the gravitational field strength is g. Which statement about these quantities is correct?

• m and W are both forces.

• m and W are both vector quantities.

• m and W have the same unit.

Each diagram shows a metal plate with four parallel forces acting on it. These are the only forces acting on the plates. In which diagram is the plate in equilibrium?

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A ship travels due North through still water at a speed of 20 m/s. It enters a channel where there is a current in the water from West to East. The speed of the current is 20 m/s. Which diagram shows the resultant velocity v of the ship?

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The engine of a car produces a driving force of 5000 N on the car. Resistive forces R also act on the car, as shown.

The car has a mass of 800 kg and an acceleration of 1.0 m/s². What is the value of R?

• 800 N

• 4200 N

• 5800 N

• 8000 N