Question

An object of Mass 10 kg dropped from a height of 100m find its kinetic energy and velocity just its reaches g
round

Answer 1

v² = u²+2 a s

v² = 2(10)(100) = 2000

v = 20 √4 ms⁻²

KE = $\frac{m v^{2} }{2}$ = 10(2000)/2 = 10000J

Answer 2

A body of mass 10kg is dropped from a height of 100m.
so, initial velocity , u = 0
displacement covered by body , S = 100m
Let final velocity of ball is v

use formula v² = u² + 2aS
here u = 0, a = -10m/s² and S = -100m [negative sign show body is below the reference level ]
so, v² = 0 + 2(-10)(-100)
v² = 2000
v = 20√5 m/s²


so, kinetic energy = 1/2 mv²
= 1/2 × 10 × (20√5)²
= 5 × 2000 = 10000 J