A canister is approaching a 78.4 kg astronaut at 3.5 m/s in an airless spacecraft. She pushes against it, which slows it down to 1.2 m/s (but does not reverse it) and gives her a speed of 2.4 m/s. What is the mass of this canister?

76.3 kg
55.6 kg
81.8 kg
90.0 kg

Arailroad car collides with and sticks to an identical railroad car that is initially at rest. after the collision, the total kinetic energy of the two cars is a) the same as before. b) half as much as before. c) one third as much as before. d) one fourth as much as before. e) twice as much as before.

Which of the following examples illustrates static friction? a box sits stationary on a ramp. a ball rolling on the lawn eventually comes to rest. a car rounds a curve on a road. a fish swims upstream.

An object is placed in front of a concave mirror between the pole and the focus of the mirror, what is the nature of the image formed by the mirror