Calculating Work Done on a 16kg Crate by Force and Weight

In summary, the question involves finding the work done on a 16 kg crate by both the applied force and the weight of the crate. The work done by the applied force is 79.1 J, but the work done by the weight of the crate is dependent on the direction and split into two parts. The correct calculation for the work done by gravity will take into account the direction and the portion of the weight acting parallel to the incline.
  • #1
perfect_piccolo
24
0
1. To push a 16 kg crate up a frictionless incline, angled at 15° to the horizontal, a worker exerts a force of 52.8 N, parallel to the incline. As the crate slides 1.50 m, how much work is done on the crate by the worker's applied force? b]

So I got the first part of this question without any problem. The answer is 79.1 J.

Its the next part of the question that I'm unsure about:

How much work is done on the crate by the weight of the crate?


I tried W=Fg(delta x)
W=156.8 N (1.5 m)
W = 235.2 J

But this obviously isn't right. Where am I going wrong?

Thanks!
 
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  • #2
How much of the weight is acting parallel to the plane?
When you do your FBD mg gets split up into 2 parts, one is perpendicular to the incline, the other is pointed down the incline. You take that portion of the weight * the distance to get the work gravity does.
Also take direction into account, is gravity opposing the motion or helping move the crate?
 
  • #3
Is anyone other than me bothered by this question?
 

1. How do you calculate work done?

To calculate work done, you multiply the force applied by the distance moved in the direction of the force. The formula for work done is W = Fd, where W is work, F is force, and d is distance.

2. What is the unit of work?

The unit of work is joule (J) in the SI system. It is defined as the amount of work done when a force of 1 newton is applied to an object and moves it a distance of 1 meter in the direction of the force.

3. How do you calculate force?

To calculate force, you divide the weight of the object (mass x acceleration due to gravity) by the distance moved. The formula for force is F = mg/d, where F is force, m is mass, g is acceleration due to gravity, and d is distance.

4. Can you calculate work done without knowing the distance?

No, it is not possible to calculate work done without knowing the distance. In order to calculate work done, both the force applied and the distance moved in the direction of the force are required.

5. How does the weight of the object affect the work done?

The weight of the object does not directly affect the work done. However, the weight is used to calculate the force applied, which is a factor in the calculation of work done. Therefore, a heavier object will require more force to be moved the same distance, resulting in more work done.

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