physics

If the speed of a moving object is doubled, which quantity also associated with the object must double? 

*A. Momentum 

B. KE

C. Gravitational potential energy

D. Acceleration

A 45 kilogram bicyclist climbs a hill at a constant speed of 2.5 meters per second by applying an average force of 85 Newtons. Approximately how much power does the bicyclist develop? 

A. 115 W

*B. 210 W 

C. 250 W

D. 320 W

 A person kicks in a 4.0 kilogram door with a 48 Newton force causing the door to accelerate at 12 meters per second squared. What is the magnitude of the force exerted by the door on the person? 

A. 24 N

B. 35 N

C. 42 N

*D. 48 N