Free Body Diagram, Newton's 3rd

[myxomatosii]

[SOLVED] Free Body Diagram, Newton's 3rd

SOLVED

Homework Statement

A 1200 kg car pushes a 2000 kg truck that has a dead battery. When the driver steps on the accelerator, the drive wheels of the car push against the ground with a force of 4700 N.

(a) What is the magnitude of the force of the car on the truck?
(b) What is the magnitude of the force of the truck on the car?

Homework Equations

f_s=\mu_sn
F=ma
F_netc/m_c=F_netT/F_T

The Attempt at a Solution

I drew this free body diagram, I am not really sure how to set this problem up but I thought this would be a good start.

Wanted to see how "right" it is.

n_c = normal force of car
n_T = normal force of truck
f_sc = static friction force
F_{c on T} = force of car on Truck
F_{T on c} = force of Truck on car
m_cg = weight of car
m_Tg = weight of truck

http://img27.imageshack.us/img27/8660/fbda88b.jpg


I've done a little dabbling with formulas from there but nothing great. I haven't solved anything so.. maybe I can at least figure out if my drawing is right.

 

[sArGe99]

Newton's Third Law of Motion?

 

[myxomatosii]

Solved! Used the materials forum on this site.

I know people google questions like these a lot, at least I do. You will find a very good lecture on this exact problem at the link I will provide, 16 minutes into Lecture 6.


http://www.free-ed.net/free-ed/Science/Physics/physicsMIT01_VOD.asp

 

[sArGe99]

But if you know the concept correctly, you can solve pretty much any problem based on that.

 

[myxomatosii]

But if you know the concept correctly, you can solve pretty much any problem based on that.

I hope so, I'm trying it out now.

To tell you the truth I've been studying these ideas for the past 7 hours and I'm becoming quite tired... so I don't know how well I can apply them at the moment. Normally I am at work right now but I called out to spend the whole night on this.