Question

You are walking around your neighborhood and you see a child on top of a roof of a building kick a soccer ball. The soccer ball is kicked at 37° from the edge of the building with an initial velocity of 17 m/s and lands 61 meters away from the wall. How tall, in meters, is the building that the child is standing on?

Answer 1

We will find the net time of flight of the ball using, the x-component of velocity and the horizontal distance it has travelled. then we will use this time to calculate the height of the building.

[note: upwards is taken as positive y-axis]

distance travelled on x is 61 m

hence the time of flight is

using the equation of motion along the y-axis

..................................equation (a)

s=H

u=v_oy

a=-9.8m/s²

t=4.5s

putting these values in the above equation (a)

Hence the height of the building is 53.2m