Review Time] Can't Answer That Question...

[pebbles]

Review time; came across that question in the text...I DON'T KNOW!

...i hate this class.

:"[

 

[learningphysics]

what is the total work done on a block sliding up a frictionless plane?

Is the block slowing down or speeding up?

What does the work-energy theorem say?

 

[pebbles]

block would be slowing down right, if it's going up?

work-energy thm. says W= change in kinetic energy...

 

[TMM]

It's negative, because the projection of the force of gravity on the displacement up the ramp is in the opposite direction.

 

[learningphysics]

block would be slowing down right, if it's going up?

work-energy thm. says W= change in kinetic energy...

exactly... so since it is slowing down... change in kinetic energy is negative... so work done on the block is negative.

 

[pebbles]

ok. i think i get it.

thanks guys! :]