A6.5×10−2 kg arrow hits the target at 25 m/s and penetrates 3.8 cm before stopping.
a) what average force did the target exert on the arrow? b)what average force did the arrow exert on the target? c)an identical arrow strikes the target at 65m/s . if the target exerts the same average force as before, what's the penetration depth?

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.