Question

A ball is dropped from height of 45 m. A second ball is thrown downwards from the same

with an initial vity both the balls reach the ground at the same time, culate the value of u​

Answer 1

h = 45 m

g(acceleration due to gravity) = 9.8 m/s^2 or 10 m/s^2

Final velocity ( v ) = 0 m/s

v = ?

we know theirs equation of motion, v^2 = u^2 + 2gh

0 = u^2 + 2(-10)(45) [ The acceleration due to gravity is ALWAYS negative. Any object affected only by gravity (a projectile or an object in free fall) has an acceleration of -9.81 m/s2, regardless of the direction. The acceleration is negative when going up because the speed is decreasing.]

0 = u^2- 900

900 = u^2

u = √900 = 30 m/s