1. A 660 kg car is moving with an initial speed of 10.0 m/s. A deer jumps into the road and the driver slams on his brakes, honks the car's horn, and says a prayer silently as he swears out loud. The car comes to a screeching halt after 4.00 seconds, just inches from the deer, which then nonchalantly proceeds to cross the road and get hit by a dumptruck coming from the opposite direction. What average power is used to stop the car, in Watts?
2. A ball of mass 2.00 kg is tossed to a height of 13.0 m above the ground. If the ball is thrown straight up and air resistance is neglibile, how fast will it be going when it hits the ground, in m/s?
3. You pick up a barbell with weights (total mass: 100 kg) from ground to approximately 0.80 m above the ground (roughly equivalent to doing a dealift). Once it has been lifted, you then carry it 10.0 m ata steady speed before stopping and finally gently lowering the barbell back to the ground. How much work have you done on this barbell, in J?