Simple coefficient of friction problem

AI Thread Summary
The discussion centers around a friction problem involving a 1,450 kg car sliding on wet concrete at a constant speed of 3.00 m/s while being pulled by a force of 3.45 x 10^3 N. Participants express confusion over whether the problem is correctly formulated, particularly regarding the forces acting on the car and the coefficients of friction provided. The key point is that the force applied should be sufficient to overcome static friction for the car to slide, yet it seems inadequate for both starting from rest and maintaining motion. The problem requires finding the coefficient of sliding friction and the car's acceleration after 3.50 seconds, emphasizing the need to interpret the scenario correctly. Overall, the discussion highlights the complexities of understanding friction in dynamic situations.
jsel21
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Did my teacher incorrectly write this problem? I looked at it for a good 20 minutes straight before posting this on here.. It's so easy but I think there is something wrong.

1.) The Wheels of a 1.450 x 10^3 Kg car car are locked so that it can only slide on wet concrete at a constant speed of 3.00 m/s when pulled by a horizontal force of 3.45 x 10^3 N.
(a) Find the coefficient of sliding friction for rubber on when concrete.
(b) what is the acceleration of the car after 3.50s?

Coefficient of kinetic friction of rubber on wet concrete - 0.5 (given in book)
Coefficient of Static friction of rubber on wet concrete - 0.7 (given in book)


]Normal Force = mg
Friction Force = Friction Coefficient x Normal Force

What's strange about this is that it seems that 3.45 x 10^3 N is not enough either to get the locked wheels to slide when from rest or already in motion. So i don't see how it can be sliding at 3.00 m/s in the first place.
 
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A body that is still is more difficult to move than a moving body (static and kinetic friction). So, assume that the body in your exercise is already moving.
 
Read the problem again. Constant speed! Equilibrium condition!
 
jsel21 said:
Coefficient of kinetic friction of rubber on wet concrete - 0.5 (given in book)
Do not assume this. You are asked to find the coefficient of sliding friction, per above replies.
 

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