- #1
Abu
Homework Statement
What is the minimum work needed to push a 1000-kg car 300 m up a 17.5 degree incline?
A. Ignore friction
B. Assume the coefficient of friction is 0.25
Homework Equations
W = F*d
Net force = ma
The Attempt at a Solution
At first I did:
Work = F*300*cos17.6
but I later realized that the force and distance are both in the same direction, thus the angle would be 0
So that means that the new formula is Work = ma*300... but what is a? Acceleration is equal to force applied minus force of friction divided by mass, but the force applied is not known, and for part A friction is not included.
So I've already looked at other solutions and I found the answer, but I don't understand why it is done this way. Basically the minimum work is equal to mg*300sin17.5.
My question is how come this equation is used instead? Is the work that it takes to lift the car straight upwards the height of the incline equal to the work that it takes to push the car all the way up the inclined, and if so, how come?
Thanks.