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Using a ramp decreases work?

by missmallyb
Tags: decreases, ramp, work
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missmallyb
#1
Dec8-10, 06:08 PM
P: 5
If one were asked, "How does a ramp make it easier to move a heavy object a certain distance?" Would you answer with
a. by changing the direction in which the object move
b. by decreasing the amount of work required to move the object
c. by decreasing the distance the object moves
d. by decreasing the amount of force required to move the object

I said "Decreasing the amount of force required to move the object" but it's incorrect. The correct answer is B, "Decreasing the amount of work required to move the object"
Can someone explain to me why my first answer was wrong?

Thanks,
-Mally
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Danger
#2
Dec8-10, 06:15 PM
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It's a crap question, to me. A ramp increases the mechanical advantage that aids you in doing whatever you're doing. That is why a screw is such an engineering marvel... it's an endless ramp. It does come down to work, but it doesn't make it easier; it merely spreads it over time. No matter what mechanism is involved, you are never going to get off easily. You can't violate Thermodynamics.
Doc Al
#3
Dec8-10, 06:20 PM
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I'd say your answer is correct. The purpose of a ramp is allow you to raise a heavy object using less force than you would if you just lifted it directly. The work done is the same.

I'd also say that moving a heavy object 'a certain distance' is ambiguous wording. The point is to lift the object, not just move it some distance.

berkeman
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Dec8-10, 06:22 PM
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Using a ramp decreases work?

Quote Quote by missmallyb View Post
If one were asked, "How does a ramp make it easier to move a heavy object a certain distance?" Would you answer with
a. by changing the direction in which the object move
b. by decreasing the amount of work required to move the object
c. by decreasing the distance the object moves
d. by decreasing the amount of force required to move the object

I said "Decreasing the amount of force required to move the object" but it's incorrect. The correct answer is B, "Decreasing the amount of work required to move the object"
Can someone explain to me why my first answer was wrong?

Thanks,
-Mally
I would have answered the same as you. The ramp lets you use less force, but applied over a longer distance compared to straight lifting the object.

Is there a figure that goes with this question? I wonder if the ramp arrangement that they have in mind is different in some way. Are they talking about the work to lift an object up some height, and is the ramp assumed to be frictionless?


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