Fnet=P-Pc=24-117.6=-93.6NFind Force Needed to Move 4kg Box in 3s

  • Thread starter Thread starter bearsa113609
  • Start date Start date
  • Tags Tags
    Box Force
AI Thread Summary
To find the force needed to move a 4kg box from rest to a velocity of 6m/s in 3 seconds, the acceleration is calculated as 2m/s². The gravitational force acting on the box is 39.2N, and the force of friction, given the coefficient of friction of 0.05, is 1.96N. The net force required for the box to achieve the desired acceleration is 8N. Therefore, the total applied force must overcome both friction and provide the net force, resulting in a required force of 49.16N. This calculation confirms the necessary force to move the box under the given conditions.
bearsa113609
Messages
2
Reaction score
0

Homework Statement


A certain force moves a 4kg box from rest to a velocity of 6m/s in 3 seconds. If the coefficient of friction between the box and floor is 0.05, what is the magnitude of the force?

m=4kg
v0=0
v=6m/s
t=3s
μk=0.05

Homework Equations


a=v/t
F0=mg
P=Ft
P=mv

The Attempt at a Solution


a=(6)/(3)=2m/s
F0=(4)(9.8)=39.2N
Pc=(39.2)(3)=117.6
P=(4)(6)=24
 
Physics news on Phys.org


bearsa113609 said:

Homework Statement


A certain force moves a 4kg box from rest to a velocity of 6m/s in 3 seconds. If the coefficient of friction between the box and floor is 0.05, what is the magnitude of the force?

m=4kg
v0=0
v=6m/s
t=3s
μk=0.05

Homework Equations


a=v/t
F0=mg
P=Ft
P=mv

The Attempt at a Solution


a=(6)/(3)=2m/s
F0=(4)(9.8)=39.2N
Pc=(39.2)(3)=117.6
P=(4)(6)=24

HINT:
You've found the acceleration. Can you use that to find the net force, and then, from there, the unknown applied force?You don't need momentum or impulse for this problem.
 


thank you so much
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top