If a projectile is fired straight up at a speed of 30 m/s, the total time (up and down) to return to its starting point is about *
-3 s
-4.5 s
-6 s
-7.5 s

If an astronaut takes an object to the moon the following is true (choose only one). a the mass will change but the weight will be the same. b both the mass and the weight of the object will be the same. c the weight will change but the mass will be the same. d both the mass and the weight of the object will change.

Arowboat passenger uses an oar to push the boat off the dock by exerting a force of 40n for 3.0s. what impulse acts on the boat.

How do i solve this physics problem?