A fast bowler runs in to bowl and releases the ball froma height of 2.4m above the ground at a speed of 144km/h at an angle of 7 degrees below the horizontal. Take the origin to be the point where the ball is released and g=-10m/s/s.

(a) show that the coordinates of the ball after t seconds is given by

1) x=40t cos 7 and

2) y=2.4-40t sin 7-5t^2

My question is where did the 40 come from and where has the velocity of 144km/h gone?

Thank you