19. When 100 J are put into a device that puts out 60 J, the efficiency of the device is (1 Point)
O 40%.
O 50%
O 60%
O 140%
NEED ASAP

As a car drives with its tires rolling freely without any slippage, the type of friction acting between the tires and the road is 100) a) static friction. b) kinetic friction. c) a combination of static and kinetic friction. d) neither static nor kinetic friction, but some other type of friction. e) it is impossible to tell what type of friction acts in this situation.

The difference between a red shift and a blue shift has to do with wavelength frequency. t or f

Using a pedometer, you walk 3000 steps in 20 minutes, so your speed is 150 steps/min. each of your steps is 0.7 m long. what is your speed? 150 steps/min=/s=/h