9709 P43 - Jun 2010 - Q3
3571
A load is pulled along a horizontal straight track, from A to B, by a force of magnitude P N which acts at an angle of 30° upwards from the horizontal. The distance AB is 80 m. The speed of the load is constant and equal to 1.2 m s-1 as it moves from A to the mid-point M of AB.
- For the motion from A to M the value of P is 25. Calculate the work done by the force as the load moves from A to M.
The speed of the load increases from 1.2 m s-1 as it moves from M towards B. For the motion from M to B the value of P is 50 and the work done against resistance is the same as that for the motion from A to M. The mass of the load is 35 kg.
- Find the gain in kinetic energy of the load as it moves from M to B and hence find the speed with which it reaches B.
