Question

A stone is thrown horizontally with speed 30m/s from a tower of 50m. The height of stone from ground at which it makes 45 degree with horizontal is

Answer 1

initial speed of the block is 30 m/s horizontally

now the velocity of block will make 45 degree with the horizontal

so it means the vertical component of velocity will be same as that of initial horizontal velocity at the instant of time

so we can say

$v_y = v_x = 30 m/s$

also for vertical direction we can say

$v_y = v_i + at$

$30 = 0 + 10 * t[\tex]</p><p>[tex]t = 3 s$

now we can say that this will be done after 3 s of motion so the distance covered in 3 s time will be given as

$y = \frac{1}{2} gt^2$

$y = \frac{1}{2}*10*3^2 = 45 m$

so the object will dropped by 45 m from its initial position

so the height of the object from ground will be

$H = 50 - 45 = 5 m$

so its height will be 5 m from the ground