Power required to move up an incline

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    Incline Power
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Homework Help Overview

The discussion revolves around calculating the power required for a car to ascend a 10% grade incline at a speed of 60 km/h. The problem involves concepts from mechanics, particularly forces acting on an object moving along an incline.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to analyze forces acting on the car using free body diagrams and equations related to motion. Some participants suggest considering the rate of change of potential energy, while others note the constraints of the curriculum, emphasizing the use of work and power formulas instead.

Discussion Status

The discussion is ongoing, with participants exploring different approaches to the problem. There is a recognition of the need to calculate the force of gravity acting along the incline, and some guidance has been provided regarding the relationship between work and power in this context.

Contextual Notes

Participants mention that they have not yet covered energy concepts in their coursework, which influences their approach to solving the problem. There is also a focus on using specific formulas related to work and power rather than energy considerations.

Ut Prosim
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Homework Statement



What power is needed to drive a car at 60 km/h up a 10% grade.

mass=1800kg
v=60km/h
theta=5.7106
g= 9.81 m/s^2

Homework Equations



P = Fv
P_ave= W/T
w=mg
F=ma

The Attempt at a Solution



I drew my diagram and FBD.

Since Fy=mAy=0..

0=N-sin(5.7106)
N=1755.2477

I know that Ax will be 0 since the velocity is constant, and I need to find the frictional constant:

mAx=0=F-uk-mgcos(5.7106)

But I don't have F, since it's what I'm trying to find..and this is where I've been stuck.
 
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Welcome to PF.

Maybe consider the rate of change of potential energy?
 
Problem with that is we haven't learned anything about energy yet so we are supposed to use regular Work, Power, and other Motion formulas.
 
Ut Prosim said:
Problem with that is we haven't learned anything about energy yet so we are supposed to use regular Work, Power, and other Motion formulas.

OK. So consider then the force of gravity along the incline.

The car travels at 16.667 m/s, so in 1 second, what force was required to overcome gravity over that distance?

That gives you W per sec = F*d per sec.
 

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