Non-uniform Motion (CIE A Level Physics)

A car has a horizontal driving force of 2.0 kN acting on it and a resistive force a quarter of this size. It has a forward horizontal acceleration of 2.0 m s^–2

What is the mass of the car?

A stone of mass m is dropped from a tall building. There is significant air resistance. The acceleration of free fall is g.

When the stone reaches its terminal velocity, which information is correct?

	Magnitude of the acceleration of the stone	Magnitude of the force of gravity on the stone	Magnitude of the force of air resistance on the stone
A B C D	zero g g zero	mg mg zero zero	mg mg zero zero

A wooden block rests on a rough board. The end of the board is then raised until the block slides down the plane of the board at constant velocity v

Which row describes the forces acting on the block when sliding with constant velocity?

	Frictional force on block	Resultant force on block
A B C D	down the plane down the plane up the plane up the plane	zero down the plane zero down the plane

A block of mass 1.20 kg is on a rough horizontal surface. A force of 12 N is applied to the block and it accelerates at 4.0 m s⁻²

What is the magnitude of the frictional force acting on the block?

A boat travels forward in a straight line. The driving force of the boat is less than the water resistance acting on the boat.

Which statement is true?

The three forces acting on a hot-air balloon that is moving vertically are its weight, the force due to air resistance and the upthrust force.

The hot air balloon descends vertically at constant speed. The force of air resistance on the balloon is F.

Which weight of material must be released from the balloon so that it ascends vertically at the same constant speed?

A skydiver falls vertically from a stationary balloon. 

She leaves the balloon at time t = 0. At time t = T, she reaches terminal velocity. Beyond the time shown in the graphs, she opens her parachute

Which graph shows the variation with time t of the force F due to air resistance?

Two skydivers, A and B, experience drag forces D₁ and D₂ respectively. Skydiver A has mass m and reaches terminal velocity v₁. Skydiver B has mass 2m and reaches terminal velocity v₂. 

Given that , what is the value of ?

A car of mass m starts from rest and reaches a velocity of v over distance s. The car experiences a frictional force of , where W is the weight of the car, and has constant acceleration.

What is the driving force of the car?

Fig. 1.1 shows two blocks, A and B, that have masses of 3m and 2m respectively. A force, F, is applied to Block A, and both blocks accelerate along a horizontal surface. Block B experiences a drag force of .

Fig. 1.1

What is the resultant force of Block A on Block B?