Normal Force, Static and Kinectic Friction.

In summary, a block with a weight of 41.0 N and coefficients of static and kinetic friction of 0.650 and 0.420 N is subjected to a horizontal force of 48 N. The maximum static frictional force is 26.65 N and since the applied force is greater, the block will move with an acceleration of 1.44 m/s^2. Using Newton's Second Law, the acceleration can also be calculated by dividing the kinetic frictional force (2.14 N) by the mass (4.1836 kg).
  • #1
stillborndesire
1
0
1.
A block whose weight is 41.0 N rests on a horizontal table. A horizontal force of 48 N is applied to the block. The coefficients of static and kinetic friction are 0.650 and 0.420 N, respectively. Will the block move under the influence of the force, and, if so, what will be the block's acceleration? (If not, enter 0.)



2. W (weight) = mg (mass)(9.8m/s^2)= normal force (FN), FsMAX (maximum static frictional foroce) = μs (coefficient of static friction) x FN, Ax (acceleration in x component) = Fk (kinetic frictional force) / m = ( μk x FN) / m. μk = coefficient of kinetic friction

Attempt 1)
3.
Attempt 1)
FsMAX = μs x FN
= (.650 x 41)
= 26.65
48 (Horizontal force) > 26.65 --> acceleration will occur
Ax = Fk/m
= μk x Fn / m
= (.420 x (41 - 26.65) ) / (41 / 9.8)
= (.420 x 14.35) / 4.1836
= 1.44 m/s ^2
----------------------
Attempt 2)
Ax = Fk/m
= μk x Fn / m
= (.420 x (48 - 26.65) ) / (41 / 9.8)
= (.420 x 21.35) / 4.1836
= 2.14 m/s ^2
 
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  • #2
Remember that the acceleration will be given by Newton's Second Law:

[tex]a=\frac{\Sigma F}{m}[/tex]

What is [tex]\Sigma F[/tex]?
 
Last edited:
  • #3

The block will move under the influence of the force, with an acceleration of either 1.44 m/s^2 or 2.14 m/s^2, depending on the starting position of the block. The coefficients of static and kinetic friction play a crucial role in determining the block's movement. The maximum static frictional force must be overcome by the applied force in order for the block to start moving. Once the block is in motion, the kinetic frictional force will be less than the maximum static frictional force, resulting in a lower acceleration. This illustrates the importance of understanding the different types of friction and how they affect the movement of objects. As a scientist, it is important to accurately calculate and consider these factors in order to make accurate predictions and explanations about the behavior of objects in different situations.
 

1. What is normal force?

Normal force is the force that a surface exerts on an object in contact with it. It is always perpendicular to the surface and acts to prevent the object from passing through the surface.

2. How is normal force related to weight?

Normal force is equal in magnitude and opposite in direction to the weight of an object when it is resting on a horizontal surface. This means that when an object is not accelerating, the normal force and weight are balanced.

3. What is static friction?

Static friction is a force that opposes the motion of an object when it is at rest. It occurs when two surfaces are in contact and prevents the object from sliding or moving.

4. How is static friction different from kinetic friction?

Static friction acts on objects that are at rest, while kinetic friction acts on objects that are in motion. Additionally, static friction is typically greater than kinetic friction, meaning it takes more force to overcome static friction and start an object moving.

5. What factors affect the amount of friction between two surfaces?

The amount of friction between two surfaces is affected by the types of materials and their roughness, the force pressing the surfaces together, and the presence of any lubricants. Additionally, the surface area in contact and the temperature can also affect the amount of friction.

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