Will the Farmer Move the Stubborn Mule?

[ideefixem]

Homework Statement

A stubborn 120 kg mule sits down and refuses to move. To drag the mule to the barn, the exasperated farmer ties a rope around the mule and pulls with his maximum force of 800 N. The coefficients of friction between the mule and the ground are mu,s = 0.8 and mu,k = 0.5. Is the farmer able to move the mule?

The attempt at a solution

friction=μs(normal force)
friction=0.8(120kg)
friction=120(9.8)(.8)
frictionS=940.8
940.8N>800N

The farmer will not be able to get the mule to move.


Does this look correct?

 

[G01]

Looks good to me. By the way, is this problem from Knight's book? I know I remember it from somewhere...

 

[ideefixem]

Haha, quite the memory. Yep, taken right from the book.

 

[G01]

Haha, quite the memory. Yep, taken right from the book.

I tutor intro physics and they use that book at my university, so I must have done it recently at a tutoring session. So, my memory isn't that great.