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DanDanDan
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Homework Statement
a 1500 kg car is moving up a 25 degree incline at a constant speed of 30 mph. the tires and road have an effective friction coefficient of u = 0.25 . determine the power output the engine must provide to keep the car moving at this speed. express your final answer in units of watts and horse-power. if an answer cannot be found then briefly explain why this is so.
Homework Equations
Wnet = E_final - E_initial
Power = Work / Time
Power = Force (dot) Velocity
KineticE= 1/2 * Mass * Velocity^2
F_friction= u * F_normal
The Attempt at a Solution
I assumed the answer can be found...
step 1:
I initially drew a Free Body Diagram:
Normal - perpendicular to the incline pointing above it
Push - parallel to the incline pointing up it
Friction - parallel to the incline pointing down it
MG - straight down
Step 2:
This is where I am stuck. What I believe I am trying to find is the energy consumed per time unit overcoming friction PLUS the energy consumed per time unit to keep the car moving at 30mph. If this is correct I still am struggling with how to use the equations to find power.(mostly how to go from Force to Work to Power)
my attempt to set up the equation:
30mph = 13.4112m/s
F_f = .25 * sin(65) * 1500 * 9.8 = 3330.68 N
W_f = 3330.68 * delta X
Above where would I even get (delta X)
KE= (1/2) * 1500 * 13.4112^2 = 134895 J
W_f + KE = Total Energy
after this I don't have a time defined to turn work to power