Answer to Question #91701 in Classical Mechanics for Louie

Question

A rocket of mass 14500kg accelerates at 210m/s2 for 32s from an initial speed of 5100m/s. (a) How fast will be rocket be travelling after the 32s?
(b) How much Kinetic Energy has the rocket gained?

Answer 1

a)

$$v=v_0+at=\\ = 5100+210\times 32= 11820 \frac{m}{s}$$

b)

$$E_{kin}=\frac{mv^2}{2}\\ \Delta E_{kin}=\frac{mv^2}{2}-\frac{mv_0^2}{2} = \\ \frac{14500\times 11820^2}{2}-\frac{14500\times 5100^2}{2} = 824 TJ$$