Physics question a spacecraft descends vertically near the surface of planet x. an upward thrust of 25.0kn from its engines slows it down at a rate of 1.20 m/s^2, but if an upward thrust of only 10.0 kn is applied, it speeds up at rate of .80m/s^2.

What do you think car designers do if the damage caused by a crash test is too severe?

What is the coefficient of kinetic friction μk between the block and the tabletop?

Air is contained in a variable-load piston-cylinder device equipped with a paddle wheel. initially, air is at 400 kpa and 17°c. the paddle wheel is now turned by an external electric motor until 75 kj/kg of work has been transferred to air. during this process, heat is transferred to maintain a constant air temperature while allowing the gas volume to triple. calculate the required amount of heat transfer in kj/kg.