A ball is thrown straight up at a speed of 10 m/s and a height of 20 m. If the ball falls all the way to the ground, how long will it take from when it's thrown? How fast will it be going when it hits the ground?

Consider two less-than-desirable options. in the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. in the second option you are driving 30 mph and crash head-on into a stationary brick wall. in neither case does your car bounce off the thing it hits, and the collision time is the same in both cases. which of these two situations would result in the greatest impact force?