# Energy dissipated by friction

cmed07
I need help figuring out the equation for E :

Find the amount of energy E dissipated by friction by the time the block stops. Express your answer in terms of some or all the variables m, v, and h and any appropriate constants.

Homework Helper
Gold Member
I need help figuring out the equation for E :

Find the amount of energy E dissipated by friction by the time the block stops. Express your answer in terms of some or all the variables m, v, and h and any appropriate constants.
You'll ned to furnish a sketch or more info, and an attempt at a solution, before we can help...

Sovos
Since the problem states "by the time the block stops." we can assume the final energy is purely potential energy.

So one possibility could be finding the initial potential and kinetic energy and subtracting the final potential energy from those.

KEi+PEi-PEf=Energy lost

Then plug in your variables for KE and PE

This is assuming energy is not being lost due to any force other than friction.

Homework Helper
Gold Member
Since the problem states "by the time the block stops." we can assume the final energy is purely potential energy.

So one possibility could be finding the initial potential and kinetic energy and subtracting the final potential energy from those.

KEi+PEi-PEf=Energy lost

Then plug in your variables for KE and PE

This is assuming energy is not being lost due to any force other than friction.
Yes, looks very good! You even got the plus and minus signs correct Now just adapt that to your given problem.

cmed07
Since the problem states "by the time the block stops." we can assume the final energy is purely potential energy.

So one possibility could be finding the initial potential and kinetic energy and subtracting the final potential energy from those.

KEi+PEi-PEf=Energy lost

Then plug in your variables for KE and PE

This is assuming energy is not being lost due to any force other than friction.

Thanks! This helped me a lot :)