A 68.9 kg woman and her 31 kg son are standing at rest on an ice rink. They push against each other for a time of 0.73 s, causing them to glide apart. (Assume friction is negligible during the push.) The speed of the woman immediately after they separate is 4 m/s.

Two astronauts, of masses 66.7-kg and 87.7-kg, are initially right next to each other and at rest in outer space. They suddenly push each other apart.  What is their separation after the heavier astronaut has moved 10.5-m? Provide your final answer in meters.

Two ice skaters, initially at rest, push each other so that they move in opposite directions. One skater, of mass 56.9 kg has a speed of 3.28 m/s. What is the mass of the second skater if her speed is 3.69 m/s. Ignore Friction.

A 70.9-kg boy and a 43.2-kg girl, both wearing skates face each other at rest on a skating rink. The boy pushes the girl, sending her eastward with a speed of 4.64 m/s. Neglecting friction, determine the direction of the boy's motion.

Two astronauts, of masses 55 kg and 89 kg, are initially at rest in outer space.  They push each other apart.  What is their separation after the lighter astronaut has moved 10 m? Round your answer to the nearest meter.

Two stationary hockey players push each other so that they move in opposite directions. One player has a mass 38.7 kg and a speed of 2.8 m/s. What is the mass of the other player if her speed is 3.8 m/s ? Neglect friction.

Gerald and Julia drove to Baguio and is resting in their car before they go to their inn. Their parked car happens to be 15.0 m from the edge of a cliff. The car's mass, plus that of their combined masses is 1050 kg. Julia's jealous ex-boyfriend ties an improvised rope to their car's bumper and a 90 kg rock to the other end of the rope. He then lowers the rock over the edge of the cliff (assume the interaction between the cliff and the rock produce a negligible amount of friction) and the car, which is in neutral, accelerates toward the edge. Assume the car experiences 42 N of frictional force. What is the acceleration of the car towards the edge? 0.790 m/s^2 O 0.737 m/s^2 0.810 m/s^2 0.880 m/s^2

At a time when mining asteroids has become feasible, astronauts have connected a line between their 3070-kg space tug and a 5580-kg asteroid. They pull on the asteroid with a force of 307 N. Initially the tug and the asteroid are at rest, 436 m apart. How much time does it take for the ship and the asteroid to meet?

Four railroad cars, each of mass 2.50 x 104 kg, are coupled together and coasting along horizontal tracks at speed vi toward the south. A very strong but foolish movie actor, riding on the second car, uncouples the front car and gives it a big push, increasing its speed to 4.00 m/s southward. The remaining three cars continue moving south, now at 2.00 m/s. (a) Find the initial speed of the four cars. (b) By how much did the potential energy within the body of the actor change?