Question

In a movie, a monster climbs to the top of a building 30 m above the ground and hurls a boulder downward with a speed of 25 m/s at an angle of 45° below the horizontal. How far from the base of the building does the boulder land?

Answer 1

22.27 m

Step-by-step explanation:

initial velocity, u = 25 m/s

Angle of projection, θ = 45°

height, h = 30 m

Let t be the time taken to reach the ground.

use second equation of motion in vertical direction

`s = ut + (1)/(2)at^(2)`

`- 30 = -25 Sin 45* t - (1)/(2)* 9.8t^(2)`

`4.9t^(2)+17.67 t - 30 = 0`

`t=\frac{-17.67\pm \sqrt{17.67^(2)+4* 4.9 * 30}}{9.8}`

t = 1.26 second

The horizontal distance = horizontal velocity x time

d = 25 Cos 45 x 1.26 = 22.27 m