Average friction force(energy)

In summary, a 16 g bullet traveling at 51m/s pierces a 13cm thick sand bag and emerges with a velocity of 14m/s. The average magnitude of the friction force experienced by the bullet while traveling through the bag can be calculated by finding the work done due to frictional force, which is equal to the change in kinetic energy. The equation k+u=k+u? can be used for this calculation, but the student is unsure if this is the correct approach as they were initially thinking about kinematics.
  • #1
juggalomike
51
0

Homework Statement



A 16 g bullet pierces a sand bag 13cm thick. If the initial bullet velocity was 51m/s and it emerged from the sandbag with 14m/s, what is the average magnitude of the friction force the bullet experienced while it traveled through the bag?

Homework Equations



k+u=k+u?

The Attempt at a Solution


I am completely stumped on this equation, i think my problem is that i keep thinking kinematics but i don't believe that is how we are supposed to solve it as we are currently working on energy
 
Physics news on Phys.org
  • #2
Work done due to frictional force = change in KE.
 
  • #3
lol thanks
 

What is average friction force?

Average friction force is the force that opposes the motion of an object as it slides or moves across a surface. It is caused by the interactions between the surfaces of the object and the surface it is moving on.

How is average friction force measured?

Average friction force is typically measured using a device called a force sensor or a spring scale. The object is pulled or pushed along the surface while the force sensor records the amount of force required to overcome the friction force.

What factors affect the magnitude of average friction force?

The magnitude of average friction force is affected by several factors, including the type of surfaces in contact, the force pressing the surfaces together, and the roughness of the surfaces. Additionally, the velocity and temperature of the surfaces can also impact the average friction force.

How is average friction force related to energy?

Average friction force is directly related to energy. When an object is moving across a surface, the average friction force acts in the opposite direction of the motion, resulting in the conversion of some of the object's kinetic energy into thermal energy.

How can average friction force be reduced?

There are several ways to reduce average friction force, such as using lubricants between the surfaces, making the surfaces smoother, or reducing the force pressing the surfaces together. Additionally, reducing the speed at which the object moves across the surface can also decrease the average friction force.

Similar threads

Relationship between horizontal force and friction in an exercise
    • Introductory Physics Homework Help
Replies
7
Views
418
The Work of Friction: Explained in .32m
    • Introductory Physics Homework Help
Replies
8
Views
911
Two bodies connected with an elastic thread moving with friction
    • Introductory Physics Homework Help
Replies
6
Views
230
Conservation of energy problem with friction included
    • Introductory Physics Homework Help
Replies
3
Views
640
Friction - problem with one of the equilibrium equations
    • Introductory Physics Homework Help
Replies
13
Views
820
Is My Physics Calculation on Bullet and Block Interaction Correct?
    • Introductory Physics Homework Help
Replies
14
Views
3K
Find the average force at distance x
    • Introductory Physics Homework Help
Replies
22
Views
2K
Hertzian contact with friction
    • Introductory Physics Homework Help
Replies
4
Views
1K
Find the average force exerted on a bullet by a rifle
    • Introductory Physics Homework Help
Replies
1
Views
3K
Physics rifle problem -- Forces and acceleration of the bullet
    • Introductory Physics Homework Help
Replies
1
Views
1K

Hot Threads

Recent Insights

Back
Top