A52.0 kg skateboarder does a trick on a half-pipe. during the trick, he reaches a speed of 8.90 m/s. the radius of the half-pipe ramp is 3.00 meters. what is the minimum centripetal force necessary to keep the skater on the ramp?

The motor m applies a time-varying force of f (200 t) n, where t is in seconds. box b with mass 200 kg starts from rest, and the coefficients of kinetic and static friction are 0.2 and us 0.3 the acceleration due to gravity is g 9.8 m/s2 b 300 a) find the time ' when the box starts to move. b) calculate the speed of the crate at 3 s c) calculate the power delivered by the motor at t 3 s

2kg of refrigerant 134a undergoes a polytropic process in a piston-cylinder assembly from an initial state of saturated vapor at 2 bar to a final state of 12 bar, 80 degree c. a)determine the work for the process in kj. b)sketch the process on a p-v diagram.

A40.0 l tank of ammonia has a pressure of 12.7 kpa. calculate the. volume of the ammonia if it’s pressure is changed to 8.4 kpa while its temperature remains constant.