# Homework Help: Help with forces

1. Sep 29, 2004

### Angeluzmaia

Help with forces!!!!!!!!

I need help with this, I've been trying but I don't understand it. Can anyone help me?????

A 830.0 kg car travelling on a level road at 27.0 m/s (60.5 mi/hr) can stop, locking its wheels, in a distance of 61.0 m (200.1 ft). Find the size of the horizontal force which the car applies on the road while stopping.

:surprised

2. Sep 29, 2004

### Pyrrhus

try $$W = \Delta K$$

3. Sep 29, 2004

### Angeluzmaia

I don't know how is exactly that formula, but I find one, maybe it's the same.

F=m*a

$$a= (v^2-v_{i}^2)/(2* \Delta x)$$

Now I have other problem

Find the stopping distance of that same car when it is traveling up a 19.9° slope, and it locks its wheels while traveling at 33.5 m/s (75.0 mi/hr). Assume that $$\mu_k$$ does not depend on the speed.

Last edited: Sep 29, 2004
4. Sep 30, 2004

### Angeluzmaia

please help me, this is urgent...
Any formulas will be helpful

5. Sep 30, 2004

### arildno

1. What's the normal force exerted on the ground upon the car?
2. How is the magnitude of frictional force related to the magnitude of the normal force?

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