Question

A block of mass 4 kilograms is initially moving at 5m/s on a horizontal surface. There is friction between the block and the surface which causes the block to come to a complete stop. The coefficient of kinetic friction between the block and the surface is 0.5. If the system is defined as the block only, which of the following statements would be correct?

A. There is a negative change in internal energy of the system as the block comes to a stop
B. There is a positive change in internal energy of the system as the block comes to a stop
C. There is a negative work done to the system as the block comes to a stop
D. There is a positive work done to the system as the block comes to a stop

Answer 1

A

Step-by-step explanation:

if block is only system then it's internal energy decreses . if horizontal surface is also part of system then energy remain conserve.

work is negative when F and d have opposite direction