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HELP! determine work needed to push a crate up a ramp at constant speed

by dani123
Tags: constant, crate, determine, push, ramp, speed, work
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dani123
#1
Mar14-12, 05:02 PM
P: 136
1. The problem statement, all variables and given/known data

A ramp leading up to a loading platform is 3 m long and 1 m high at its highest point. If the friction is ignored, what work is needed to slide a 600-kg crate up the ramp at a constant speed?
a) 2.00 *10^2 J
b) 5.89 *10^2 J
c) 1.80 *10^3 J
d) 5.88 *10^3 J

I believe the answer is d) but I would just like someone to explain the answer to me and correct me if d) isn't the answer. THANK YOU SO MUCH, in advance :)


2. Relevant equations

a=0
Fnet=0..... because its at a constant speed
W=Ffriction=mg

3. The attempt at a solution

W=600kg*9.8m/s^2= 5.88*10^3J
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tiny-tim
#2
Mar14-12, 06:09 PM
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hi dani123!

(try using the X2 button just above the Reply box )
Quote Quote by dani123 View Post
Fnet=0..... because its at a constant speed
correct
W=Ffriction=mg
wrong, W is work, that's completely different from force

work done equals the change in energy, so you need an equation relating W and potential energy
W=600kg*9.8m/s^2= 5.88*10^3J
maybe it's right, maybe it isn't, but the reasoning is certainly wrong
dani123
#3
Mar14-12, 06:19 PM
P: 136
Ok so this may be a stupid question but is there a difference between force and energy? If so how am I suppose to calculate the energy in order to get the work required to push the crate up the ramp! Thanks so much for your time

tiny-tim
#4
Mar14-12, 06:28 PM
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HELP! determine work needed to push a crate up a ramp at constant speed

Quote Quote by dani123 View Post
Ok so this may be a stupid question but is there a difference between force and energy?
erm yeeees!

big difference

energy = work = force times distance

(for example, mg is force, mgh is energy)
you need to go back to your book, and read those chapters again, before trying any more of these questions!
dani123
#5
Mar14-12, 06:32 PM
P: 136
ops! lol its been a long day haha thank you


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