Question 1
A tennis ball travelling with a speed of 10 ms-1 rolls off a horizontal table 1.0 m high. Ignoring air resistance, determine the:
- horizontal speed of the ball just as it strikes the floor;
- time of flight of the ball in air.
[g = 10 ms-2]
Observation
This questions was quite popular among candidates. In (a), several candidates went about it wrongly using the wrong formula to score zero.In (b), majority of the candidates failed to know that “initial speed” of the ball in the vertical direction is zero thereby reducing the formula from h = ut + gt2 to h = gt2where ‘t’ is the time of flight of the ball. Performance was low.
The expected response is as stated below:
