1. two astronauts are 2.00 m apart in their spaceship. one speaks to the other. the conversation is transmitted to earth via electromagnetic waves. the time it takes for sound waves to travel at 354 m/s through the air between the astronauts equals the time it takes for the electromagnetic waves to travel to the earth. how far away from the earth is the spaceship?

Atruck going 15 kmôź°€h has a head-on collision with a small car going 30 kmôź°€h. which statement best describes the situation? (a) the truck has the greater change of momentum because it has the greater mass. (b) the car has the greater change of momentum because it has the greater speed. (c) neither the car nor the truck changes its momentum in the collision because momentum is conserved. (d) they both have the same change in magnitude of momentum because momentum is conserved. (e) none of the above is necessarily true. 2. a small boat coasts at constant speed under a bridge. a heavy sack of sand is dropped from the bridge onto the boat. the speed of the boat (a) increases. (b) decreases. (c) does not change. (d) without knowing the mass of the boat and the sand, we can’t tell.