Question

n principle, any time someone jumps up, the Earth moves in the opposite direction. To see why we are unaware of this motion, calculate the recoil speed of the Earth when a 75 kg person jumps upward at a speed of 2.0 m/s

Answer 1

Explanation:.

Given that,

Let the mass of the person be

m = 75kg

Mass of the earth is

M = 6 × 10²⁴ kg

Spend of the person is

v = 2m/s.

Let the recoil speed of the earth be V.

Using conservation of momentum

P(initial) = P(final)

Initial momentum is 0

Pi = Pf

0 = mv + MV

V = —mv/M

V = — 75 × 2 / 6×10²⁴

V = —2.5×10^-23 m/s

Therefore, the recoil speed of the earth is 2.5×10^-23 and it is very very small, therefore, it is unmeasurable.