Halfway done Force/Friction Problem

  • Thread starter ff4930
  • Start date
In summary: Thank you!In summary, a block of mass m1 = 290 g is at rest on an inclined plane at an angle θ = 30° above the horizontal. The coefficient of kinetic friction between the block and the plane is µk = 0.10. The block is attached to a second block of mass m2 = 220 g that hangs freely by a string over a frictionless and massless pulley. To find the speed of the second block when it has fallen 30.0 cm, the net force acting on the system is calculated to be .94N. Using the equation F = m*a, the acceleration is found to be 1.8 m/s^2 or 180 cm/s^
  • #1
ff4930
46
0
334537295.jpg


A block of mass m1 = 290 g is at rest on a plane that makes an angle θ = 30° above the horizontal. The coefficient of kinetic friction between the block and the plane is µk = 0.10. The block is attached to a second block of mass m2 = 220 g that hangs freely by a string that passes over a frictionless and massless pulley.
Find its speed when the second block has fallen 30.0 cm.
cm/s

What I have done:
I turned the 2 masses into kg.

M1 = .29kg and M2 = .22kg
M1 Force of Gravity = .29kg * 9.81 m/s^2 = 2.8N
M1 Normal Force = 28 * cos30 = 2.4N
M1 Parallel Force = 28 * sin30 = 1.4N
M1 Friction Force = .10 * 2.4 = .24N

M2 Force of Gravity = 2.1N

This where I am stuck, I don't know what I should do next to determine the speed of M2 when it is falling.Edit:

The Net Force would be
1.4N - .24N = 1.16N
= 2.1N - 1.16N = .94N

F = M * A
.94N = .51kg * A
A = 1.8 m/s^2

Since there is 100 centimeters in a meter
so A = 180 cm/S^2

Speed = Distance * Time
X = 30cm * T
Where T = 30/180 = .17s
30 * .17s
Speed = 5.1cm/s

Is this correct?
 
Last edited:
Physics news on Phys.org
  • #2
The Net Force would be
1.4N - .24N = 1.16N
= 2.1N - 1.16N = .94N

The friction force on m1 acts opposite the direction of motion of m1 with respect to the inclined plane and so it acts down the plane.

Once a is found, you can use v = a t and d = (1/2) a t^2 to find v.
 
  • #3
I found
F = M * A
.94N = .51kg * A
A = 1.8 m/s^2

Since there is 100 centimeters in a meter
so A = 180 cm/S^2

I found Time to be .58s
V = to be 104cm/s

Is this correct?
 
  • #4
Can someone verify if this is the correct solution? Thanks!
 
  • #5
Anyone? I just need to verify this solution before I submit it online, please.
 

1. What is the formula for calculating force?

The formula for calculating force is F = ma, where F represents force, m represents mass, and a represents acceleration.

2. How do I determine the direction of the force?

The direction of the force can be determined by the direction of the acceleration. If the acceleration is positive, the force is in the same direction. If the acceleration is negative, the force is in the opposite direction.

3. What is the relationship between force and friction?

Force and friction are directly related. As the force increases, the friction also increases. Friction acts in the opposite direction of the applied force and helps to slow down or stop an object's motion.

4. Can friction ever work in the same direction as the applied force?

Yes, in some cases, friction can work in the same direction as the applied force. This is known as static friction, and it occurs when an object is at rest and a force is applied to it.

5. How can I reduce friction in a force problem?

There are a few ways to reduce friction in a force problem. One way is to use lubricants, such as oil or grease, to create a layer between two surfaces. Another way is to use smoother materials or surfaces. Reducing the weight or mass of an object can also decrease the amount of friction in a force problem.

Similar threads

  • Introductory Physics Homework Help
2
Replies
45
Views
2K
  • Introductory Physics Homework Help
Replies
3
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
1K
  • Introductory Physics Homework Help
Replies
19
Views
11K
  • Introductory Physics Homework Help
Replies
2
Views
968
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
1K
  • Introductory Physics Homework Help
Replies
2
Views
928
  • Introductory Physics Homework Help
Replies
4
Views
3K
  • Introductory Physics Homework Help
Replies
7
Views
2K
Back
Top