Question

In 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 77.0 kgperson jumps upward at a speed of 2.10 m/s . Consult Appendix E in the textbook as needed.

Express your answer using two significant figures.

Answer 1

Solution :-

speed of the person v = 2.1 m / s

mass of the person m = 77 kg

momentum of the person = mv

According to law of conservation of momentum , momentum of theearth is eaqul magnitude of person but in opposite indirection

So , momentum of the earth = mv

                                 MV = mv

?recoil speed of the earth V = mv / M

where M = mass of earth = 5.98 * 10 ²⁴kg

? V = [ 77kg*2.1 m / s ] / [  5.98 * 10²⁴ kg]

         = 27.04*10^-24 m / s

this is speed is very low