Question

A meteoroid of mass = 565 kg has a speed of 91.0 m/s when 900 km above the Earth. It is falling vertically (ignore air resistance) and strikes a bed of sand in which it is brought to rest in 3.25 m. (a) How much work does the force of gravity do on the meteoroid on the way to the surface? Incorrect: Your answer is incorrect. GJ (b) What is the speed of the meteoroid just before striking the sand? Incorrect: Your answer is incorrect. m/s (c) How much work does the force of gravity do on the meteoroid after it hits the surface? GJ (d) How much work does the sand do to stop the meteoroid? GJ (e) What is the average force exerted by the sand on the meteor? GN (f) How much thermal energy is produced? GJ

Answer 1

(A) PE =- G M m / r

PEi = -(6.67 x 10^-11)(5.972 x 10^24)(565) / (6371 + 900)(10^3)

PEi = - 3.095 x 10^10 J

PEf = -(6.67 x 10^-11)(5.972 x 10^24)(565) / (6371)(10^3)

PEf = -3.5325 x 10^10 J

Work done = - delta(U) = 4.372 x 10^9 J

(B) 4.372 x 10^9 = 565 v^2 / 2

v = 3924 m/s

(C) work done = 565 x 9.81 x 3.25 = 18013.6 J

(D) Work done = change in KE

= KF - Ki

= - 4.372 x 10^9 J

(E) Work done = force x time

4.372 x 10^9 = F ( 3.25)

F = 1.345 x 10^9 N

(F) thermal energy produced = 4.372 x 10^9 J