# Find the total work done on 20.0N block

• bharp24
In summary, the conversation discusses a scenario where two blocks are connected by a string and move in different directions. It also explores the concept of work done on the blocks in different situations, including when there is no friction and when there is static and kinetic friction between the blocks and the table. The total work done on each block is determined by considering the forces acting on it.

#### bharp24

Two blocks are connected by a very light string passing over a massless and frictionless pulley. The 20.0N block moves 75.0cm to the right and the 12.0N block moves 75.0cm downward.

Find the total work done on 20.0N block if there is no friction between the table and the 20.0N block.

Find the total work done on 12.0N block if there is no friction between the table and the 20.0N block.

Find the total work done on 20.0N block if static friction=0.500 and kinetic friction=0.325 between the table and the 20.0- block.

Find the total work done on 12.0N block if static friction=.500 and kinetic friction=.325between the table and the 20.0N block.

For the first two, I got total work done for both individual boxes to be 0J, but this is not correct somehow. I cannot really go on with the third and fourth scenarios until I get the first two. Can someone please help??

bharp24 said:
For the first two, I got total work done for both individual boxes to be 0J, but this is not correct somehow.
How did you determine this? What forces act on each block?

i think i went ahead and added a friction force into the first 2, which zeros them out. i still get a wrong answer though when I leave the friction out. any suggestions on how to complete this problem?

Start by answering my question: What forces act on each block?

i tried it again and got it right. thanks for trying to help me out!

## 1. What is the formula for calculating work done?

The formula for calculating work done is W = F * d, where W is the work done, F is the force applied, and d is the displacement of the object.

## 2. How do you find the force applied in a given situation?

The force applied can be found by using the formula F = m * a, where F is the force, m is the mass of the object, and a is the acceleration.

## 3. What is the unit of measurement for work done?

The unit of measurement for work done is joules (J).

## 4. Can work done be negative?

Yes, work done can be negative if the force and displacement are in opposite directions. This indicates that energy is being taken away from the system instead of being added.

## 5. How do you calculate work done on a block with a variable force?

In this case, the work done can be calculated by finding the area under the force-displacement curve using integration. This takes into account the changing force over the displacement of the object.