Two space stations are at rest relative to each other and are 6.0 × 107 m apart, as measured by observers on the stations. a spaceship traveling from one station to the other at 0.90c relative to the stations passes both of them, one after the other. as measured by an observer in the spaceship, how long does it take to travel from one station to the other?

It's a snowy day and you're pulling a friend along a level road on a sled. you've both been taking physics, so she asks what you think the coefficient of friction between the sled and the snow is. you've been walking at a steady 1.5m/s, and the rope pulls up on the sled at a 32 ∘ angle. you estimate that the mass of the sled, with your friend on it, is 65 kg and that you're pulling with a force of 80 n .