1.    A 70 kg sledge is pulled along as shown below

      

If the frictional forces amount to 50 N, calculate :

       (a)             the unbalanced force acting sledge
       (b)             the acceleration of the sledge.

2.    The forces acting on a bus are shown below

 

       If the total mass of the bus and passengers is 4 500 kg, calculate:

       (a)             the unbalanced force acting on the bus
       (b)             the acceleration of the bus.

3.    The forces acting on a rocket at launch are as shown in the diagram opposite.

4.    A car of mass 1 200 kg is accelerating along a dual carriageway at a constant rate of 3 ms^-2. 

       (a)             Calculate the unbalanced force acting on the car.
       (b)             The engine force is 3 800 N. Calculate the force of friction between the tyres and the road surface.

5.    Forces acting on a train of mass 50 000 kg are as shown below.

       Calculate:

       (a)             the unbalanced force acting on the train
       (b)              the acceleration of the train