Friction force physics problem

Summary: In summary, a stockroom worker is pushing a box with a mass of 11.2kg at a constant speed of 3.50m/s^2 on a horizontal surface with a coefficient of friction of 0.20. In order to maintain the motion, the worker must apply a horizontal force of 21.9N. If the force is removed, the net force will be equal to the mass times the acceleration, which will result in deceleration. We do not know the initial or final velocity, but we can use the equation s = ut + 1/2at^2 to calculate the distance the box will slide before coming to rest.
  • #1
Alem2000
117
0
a stockroom worker pushes a box with mass 11.2kg on a horizontal surface with a constant speed of 3.50m\s^2 The coeficient of friction is (for surface of the ground and box) .20 A...what horizontal force must the worker apply to maintian the motion.. i got [tex]F_x=21.9N[/tex] which is correct and then it asks me "it the force calculated in part a) is removed, how far does the box slide before coming to rest?" Where do i start..all I have is velocity?
 
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  • #2
Once the applied force is removed,
what is the net force?
isn't net force = ma?
does that mean we have deceleration?
oh do we know initial velocity?
and what abt final velocity?
can i get the time?
hmm but s = ut + 1/2at^2 ?
so?
ah yes!

-- AI
 
  • #3


To calculate the distance the box will slide before coming to rest, we can use the equation for constant speed motion: d = vt, where d is the distance, v is the velocity, and t is the time.

In this case, we know the velocity (3.50m/s) and we can calculate the time using the formula for acceleration: a = F/m, where a is the acceleration, F is the force, and m is the mass.

Since we know the acceleration (0m/s^2, since the box is moving at a constant speed), the mass (11.2kg), and the force (21.9N, as calculated in part a), we can rearrange the formula to solve for time: t = m/a = 11.2kg / (21.9N / 11.2kg) = 11.2kg / 1.95m/s^2 = 5.74s.

Now, we can plug this time into the distance formula to find the distance the box will slide before coming to rest: d = vt = (3.50m/s) * (5.74s) = 20.09m.

Therefore, the box will slide 20.09 meters before coming to rest if the force calculated in part a) is removed.
 

1. What is friction force in physics?

Friction force is a force that resists the relative motion or tendency of motion between two surfaces in contact. It is caused by microscopic irregularities on the surfaces and is dependent on factors such as the type of surfaces, the force pushing the surfaces together, and the roughness of the surfaces.

2. How is friction force calculated?

Friction force is calculated using the equation F = μN, where F is the friction force, μ is the coefficient of friction, and N is the normal force perpendicular to the surfaces in contact. The coefficient of friction is a dimensionless value that represents the roughness and interaction between the two surfaces.

3. What is the difference between static and kinetic friction?

Static friction is the force that resists the initial motion of two surfaces in contact. It is greater than kinetic friction, which is the force that resists the motion of two surfaces that are already in motion. Static friction helps to hold objects in place, while kinetic friction slows down the motion of objects.

4. How does the weight of an object affect the friction force?

The weight of an object affects the friction force because it determines the normal force (N) in the friction force equation. The greater the weight of an object, the greater the normal force, and therefore, the greater the friction force.

5. Can friction force be eliminated?

Friction force can be reduced, but it cannot be eliminated completely. The only way to eliminate friction force is to have perfectly smooth surfaces in contact, which is not possible in real-world scenarios. However, various techniques such as lubrication and reducing the weight of objects can help to reduce friction force.

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