Work Done By a Gravitational Force

AI Thread Summary
The discussion revolves around calculating the work done by gravitational force when pushing a refrigerator up a ramp. The book states the work is -mgd, which is derived from the formula mgdcos180. A participant clarifies that if d represents the distance along the ramp, the work done by gravity can also be expressed as -mgdsin(theta) when considering height. Additionally, it is confirmed that the work done by gravitational force and gravitational potential energy are essentially the same concept but with opposite signs. The clarification helps resolve the initial confusion about the calculations involved.
xdarkelf714x
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Hi, I'm having trouble understanding this concept. A refrigerator is on a ramp of length d and it is being pushed up the ramp. What is the work done by the gravitational force? In the book it says mgdcos180 which is -mgd. I thought that the horizontal component of gravity was mgsin(theta) so the work done would by (mgsin(theta))(d)(cos180).

Also, is work done by the gravitational force difference than gravitational potential energy?

Thanks in advance.
 
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xdarkelf714x said:
Hi, I'm having trouble understanding this concept. A refrigerator is on a ramp of length d and it is being pushed up the ramp. What is the work done by the gravitational force? In the book it says mgdcos180 which is -mgd. I thought that the horizontal component of gravity was mgsin(theta) so the work done would by (mgsin(theta))(d)(cos180).
Assuming that d is the distance along the ramp and not the height, then you're correct. In terms of height (h), the work done by gravity is just F*S = -mgh, which is equivalent to -mgdsin(theta).

Also, is work done by the gravitational force difference than gravitational potential energy?
Same thing (just opposite sign).
 
Oh, I see it now. Thank you for clearing that up for me.
 

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