A sky diver jumps out of a plane 4000 meters in the air. How fast would he hit the ground ignoring Air Resistance? What prevents him hitting at this
speed?

Under the action of a constant force an object accelerates at 7.8 m/s2. what will the acceleration be if (a) the force is halved? (b) the object's mass is halved? (c) the force and the object's mass are both halved? (d) the force is halved and the object's mass is doubled?

Using gravity, an elephant can pull a mouse towards it from the ground. true or false explain why. will give brainliest if answered fast and the best explanation

What is the efficiency of an engine that does 80 j of work and exhausts 320 j of heat while taking in 400 j of heat ? a. 10% b. 20% c. 80% d. 25%