A 5kg block has an initial velocity of 15 m/s and is sliding along a surface with friction. Eventually the block comes to rest. what is the change in thermal energy of the block and the surface ?
To determine the change in thermal energy of the block and the surface, we need to consider the work done by friction to bring the block to rest.
The work done by friction can be calculated using the equation:
Work = Force of friction × Distance
The force of friction can be determined using the equation:
Force of friction = coefficient of friction × normal force
The normal force can be calculated using the equation:
Normal force = mass × acceleration due to gravity
In this case, the initial velocity of the block and the fact that it eventually comes to rest indicate that the force of friction is equal in magnitude and opposite in direction to the force needed to bring the block to rest. This force can be calculated using Newton's second law of motion:
Force = mass × acceleration
Since the block comes to rest, the acceleration is equal to zero. Therefore, the force needed to bring the block to rest is:
Force = mass × acceleration = 5 kg × 0 m/s² = 0 N
The force of friction is also equal to zero, and as a result, no work is done by friction. Consequently, there is no change in thermal energy for the block and the surface in this scenario.