How much work is done lifting a 71 kg dog 2 meters

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

For the car in the picture ,in which direction is the normal force? -into the screen -down -out of the screen -up

One hazard of space travel is debris left by previous missions. there are several thousand masses large enough to detect by radar orbiting the earth, but there are far greater numbers of very small masses such as flakes of paint. calculate the force exerted by a 0.110 mg chip of paint that strikes a space shuttle window at a relative speed of 5.00 ✕ 103 m/s and sticks, given the collision lasts 6.00 ✕ 10-8 s. such a collision chipped the window of the ill-fated challenger in june 1983, causing $50,000 of damage.