a space shuttle, with a mass of 80000kg, returns to the earth from outer space.
a) if the speed of entering the atmosphere is 7200 ms-1, what is its kinetic energy?
b) the space shuttle gradually decelerates to 90 ms-1. what is its kinetic energy then?
c) is the energy dissipated by air resistance equal to the difference between (a) and (b)? explain briefly.
i know how to calculate (a) and (b),, but i don't understand (c),, and what can i answer??
2007-01-25 15:23:47 · 2 個解答 · 發問者 Polly 2 in 科學 ➔ 其他：科學
(c) The answer is NO.
The energy dissipated by air resistance is more than the reduction in kinetic energy of the space shuttle. The difference in energy comes from the loss of gravitational potnetial energy during the re-entry of the shuttle.
2007-01-25 15:34:07 · answer #1 · answered by 天同 7 · 0⤊ 0⤋
a 1/2mv^2
b1/2 mv^2
c no ,it is because energy loss not only by air resistance,but also potential energy
2007-01-25 15:31:37 · answer #2 · answered by 暱名 7 · 0⤊ 0⤋