Need help finding coefficient of kinetic friction

AI Thread Summary
To find the coefficient of kinetic friction for a 40.0 kg crate pushed with a 150 N force at constant speed, the normal force was calculated as 392 N. Since the crate moves at constant speed, the frictional force equals the applied force of 150 N. The coefficient of kinetic friction is then determined using the formula fK = coefficient of kinetic friction × N, leading to a value of approximately 0.38. This calculation confirms that the frictional force balances the applied force, resulting in no net acceleration. The discussion concludes with the correct coefficient value.
zinniagirl
Messages
3
Reaction score
0

Homework Statement


A horizontal force of 150 N is used to push a 40.0 kg packing crate a distance of 6.00 m on a rough horizontal surface. If the crate moves at constant speed, find the coefficient of kinetic friction between the crate and the surface.


Homework Equations


fK= coeff. of kin. friction X N
Fy= -mgy + normal force


The Attempt at a Solution


I started by using Fy= -mgy + N to be 0= -40 (9.8) (cos 0) + N and found N be 392. But now I'm not sure where to go from here to find the coefficient of kinetic friction. Can anyone help?
 
Physics news on Phys.org
Constant speed means the resultant force is zero...so what is the value of the frictional force?
 
rock.freak667 said:
Constant speed means the resultant force is zero...so what is the value of the frictional force?

150 N. So the coefficient of kinetic friction would then be .38, correct?
 
Yes that should be correct.
 
Thanks!
 

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Coefficient of Friction question for a cart going down a wooden ramp
Replies
18
Views
3K
Static friction coefficient for a crate in the back of a truck
Replies
6
Views
2K
How to find the coefficient of kinetic friction
Replies
4
Views
3K
What Is the Coefficient of Kinetic Friction Between the Ramp and the Crate?
Replies
6
Views
2K
Find the Coefficient of Kinetic Friction for Crate Movement
Replies
2
Views
2K
Coefficient of Kinetic Friction
Replies
6
Views
2K
Calculating the coefficient of kinetic friction
Replies
3
Views
3K
Friction Problem of a Crate Sliding Down a Ramp
Replies
4
Views
3K
Minimal rotational kinetic energy for a gyroscope to precess
Replies
33
Views
3K
Static and kinetic friction help?
Replies
1
Views
1K

Hot Threads

Recent Insights

Back
Top