Question

Calculate the gain in k.E.of a body of mass 100kg falls through 10m in air

Answer 1

Answer:

The gain in kinetic energy of body will be 9800 J

Explanation:

initial velocity at height = 0 m/s

s(distance) = 10m

g( acceleration ) = 9.8m/^2

Using the third equation of motion v^2 - u^ = 2gs, solve

v^2 - 0^2 = 2 x 9.8 x 10

v^2= 196

v = square root of 196 = 14m/s

now v = 14m/s

formula for gain in K.E = 1/2m(v^2 - u^2)

gain in kinetic energy = 1/2 x 100 x (14 x 14 - 0 x 0)

                                    = 9800 J

Hence the gain in kinetic energy of body will be 9800 J