This question was very popular among the candidates and the performance was low. Many responding candidates drew and got the shape of the graph (trajectory) however, majority failed to label the axes of the graph and and only few indicated the initial speed
u on the graph. Some candidates also failed to realize that at the maximum height, only the vertical motion
vy = 0.
The expected answer is
- Both axes correctly distinguished
Correct shape with u and correctly shown
Vertical (component of) velocity = u sin
If time taken to reach a height is t then,
v = u sin - gt
At maximum height v = 0
0 = u sin - gt
t = u sin
g
but the projectile takes the same time to do the rest of the flight (ie trajectory is symmetrical)
Time of flight, T = 2t = 2usin
g
