8. If a man with mass 70 kg, standing still, throws an
object with mass 5 kg at 50 m/s, what will be the recoil
velocity of the man, assuming he is standing on a
frictionless surface?
a. -3.6 m/s
b. om/s
c. 3.6 m/s

Plss anybody know how to do this? ? i need the answers from a through d

20. threshold braking in the vehicle's braking system occurs when a. the brake pedal is pushed, heel on floorboard, with full foot pressure. b. the brakes are exerting full braking power, without traction loss. c. the driver begins pushing down the brake pedal, with moderate slowdown. d. the brakes just begin to take hold with a gradual slowdown.

Gasoline comes from petroleum, which is made from ancient living things. petroleum, therefore, contains a type of energy. a. heat b. nuclear c. biological d. chemical potential