# Homework Help: Sorry for Double Post but I need Help Please

1. Nov 9, 2004

### HawKMX2004

Sorry for the double post, but this edit wasnt showing up for me on other post, so i post it here.

I also came across another challenging problem, devising of an equation for Acceleration on an inclined plane.

Q: A toy car is released from rest at the top of a ramp going down to the right. Assuming that friction IS present derive an equation that could determine the acceleration of the car.

SFy - sum of forces in the y direction
SFx - sum of forces in the x direction
Fn - Force Natural
Fgy - Force Gravity in the Y-direction
Fgx - Force Gravity in the X direction
m - Mass
a - Acceleration
U - Coefficient of Friction
Fg - Force of Gracity
Ff - Force of Friction

Here is my work, though I think i went wrong with the sin and cos values

SFy = Fn - Fgy = 0
Fn = Fgy
Fn = cos(Theta)Fg
SFx = Fgx - Ff = ma
SFx = Fgx - FnU = ma
SFx = Fgx = ma + FnU
SFx = sin(Theta)Fg = ma +cos(Theta)Fg
SFx = sin(Theta)Fg / cos(Theta)Fg = ma + U
SFx = tan(Theta) = ma + U
SFx = tan(Theta) - U = ma
SFx = [tan(Theta) - U] / m = a

Once again help would be appreciated..thankz for all help and corrections

2. Nov 10, 2004

### UrbanXrisis

Okay, I'm not going to use those variables because it's too comfusing

First, a=net force/mass
U - Coefficient of Friction
Force of Friction=UmgcosX
Force of the car=mgcosX

Net Force=mgcosX-UmgcosX

a=net force/mass
a=(mgcosX-UmgcosX)/m
a=gcosX-UgcosX