Answer to Question #125863 in Mechanics | Relativity for Sammy W-S

Question

Dynamics question:
During lift off a rocket ship accelerates from rest to about 28,000 km/h and reaches an altitude of 300 km. What is the apparent weight of a 75 kg astronaut during this time (assume constant acceleration)? explain why does an astronaut feel weightless once in orbit? and state the newton law being used

Answer 1

$$W=m\frac{s}{v}+mg\\W=75\frac{300000(3.6)}{28000}+75(9.8)=3630 N$$

We used second Newton's law.

An astronaut orbiting the Earth does feel weightless because there is no ground or normal force to counteract the force of gravity. Thus, the astronaut is falling.