9. a 1.80 kg block slides on a rough horizontal surface. the block hits a spring with a speed of 2.5m/s and compresses it a distance of 13cm before coming to rest. if the coefficient of kinetic friction between the block and surface is 0.560, what is the force constant of the spring? (use non-conservative energy principle to solve this problem)

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.