A ball is projected with a horizontal velocity of 5.1 ms^-1 at a height of 2.5 xx 10^2 m. How far does it travel before it hits the ground?

1 Answer
Jun 24, 2017

The horizontal distance traveled will be s=u_xt=5.1xx7.1=36.2 m.

Explanation:

As for all projectile motion questions, we can treat the horizontal and vertical direction independently. If we ignore air resistance, the horizontal velocity will remain constant at u_x=1.5 ms^-1.

We need to calculate the time taken for the ball to fall. The initial velocity u_y in the vertical direction is 0 ms^-1.

s = u_yt +1/2a_yt^2

t = sqrt((2s)/a) (since u_y=0 and we can rearrange to make t the subject)

t = sqrt((2(2.5xx10^2))/9.8)=7.1 s

The horizontal distance traveled in this time will be s=u_xt=5.1xx7.1=36.2 m.