How to Solve for Force Needed to Move a Box on a Ramp with Kinetic Friction

In summary, the force needed to move a 50kg box up a ramp angled at 40 degrees with an acceleration of 1m/(s^2) while pulling at an angle of 15 degrees above parallel to the ramp is approximately 405.748N. However, there may have been a mistake in the calculations as the expected force was around 356N.
  • #1
Funkmaster W
12
0

Homework Statement


Find the force(F) needed to move a 50kg box up a ramp angled at 40 degrees with an acceleration of 1m/(s^2) while pulling at an angle of15 degrees above parallel to the ramp. the ramp has a frictional constant of .1
a=1m/(s^2)
m=50kg
angle of ramp=40 degrees
angle pulling box at = 15 degrees
mu(sub k) = .1
g(gravity)=9.8

Homework Equations


F=ma
F=(mu)N


The Attempt at a Solution


i drew a fbd then split things up into components and found m*g*cos(40)=375.362 and m*g*sin(40)=314.966
then to find force i combined the vectors and equations

50 = F*cos(15) - (314.966 + .1N)
N= -F*sin(15) + 375.362

from here i solved for F by plugging in for N since i had the same two variables in each equation.

50 = F*cos(15) - (314.966 + .1((-F*sin(15)) + 375.362))
50 = .966F - (314.966 -0.026F + 37.536)
402.502 = .992F
F = 405.748
now i solved this however my physics teacher said that F is around 356 but i am unable to find my mistake and was wondering if someone could help me
 
Physics news on Phys.org
  • #2
It looks like all of your math checks out to me. I think your physics teacher may have gotten his signs mixed up somewhere. I don't see where you could have gotten a magically different number.
 
  • #3
Edit to may above post: Your teacher could have accidentally done 314.966-37.536 instead of addition. Then it end up around 348.33, which is just a difference in rounding.
 

1. What is kinetic friction?

Kinetic friction is the force that opposes the motion of two surfaces that are in contact and moving relative to each other.

2. How is kinetic friction different from static friction?

Kinetic friction occurs when two surfaces are moving relative to each other, while static friction occurs when an object is not moving and is being acted upon by an external force.

3. What factors affect the magnitude of kinetic friction?

The magnitude of kinetic friction is affected by the type of surfaces in contact, the force pushing the surfaces together, and any external forces acting on the objects.

4. How is the coefficient of kinetic friction determined?

The coefficient of kinetic friction is determined by dividing the force of kinetic friction by the normal force between the two surfaces. It is a constant value that depends on the type of surfaces in contact.

5. How can kinetic friction be reduced?

Kinetic friction can be reduced by using lubricants between the surfaces, making the surfaces smoother, or reducing the force pushing the surfaces together.

Similar threads

  • Introductory Physics Homework Help
Replies
9
Views
3K
  • Introductory Physics Homework Help
Replies
1
Views
690
  • Introductory Physics Homework Help
Replies
6
Views
225
  • Introductory Physics Homework Help
2
Replies
48
Views
6K
  • Introductory Physics Homework Help
Replies
8
Views
1K
  • Introductory Physics Homework Help
Replies
2
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
2K
  • Introductory Physics Homework Help
Replies
4
Views
2K
  • Introductory Physics Homework Help
Replies
6
Views
3K
  • Introductory Physics Homework Help
Replies
13
Views
2K
Back
Top