So, the webpage title could be: Collision Force: How is it Determined?

  • Context: High School 
  • Thread starter Thread starter Miraj Kayastha
  • Start date Start date
  • Tags Tags
    Confusion Force
Click For Summary

Discussion Overview

The discussion revolves around the concept of collision force and how it is determined, particularly in the context of an object being pushed with a specific force and its subsequent motion and collision behavior. Participants explore the implications of constant acceleration, the effects of force application, and the dynamics of collisions, including varying forces depending on the nature of the collision.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether a 10 kg object pushed with a force of 60N would accelerate constantly at 6 m/s² indefinitely if resistance is neglected.
  • Another participant suggests that constant acceleration requires a continuous force, implying that the object would instead move at a uniform speed after the initial push.
  • A different participant clarifies that the object accelerates only while the force is applied and will coast at the speed reached once the force ceases, challenging the initial assumption about constant acceleration.
  • There is a discussion about the force exerted during a collision, with one participant explaining that the force depends on the deceleration experienced during the impact, which can vary significantly based on the nature of the collision.
  • Some participants agree that the maximum force during a collision is not necessarily equal to the initial pushing force and can be much larger depending on the circumstances of the impact.
  • One participant points out a potential error in a calculation regarding the force applied during a collision, suggesting a different mass should have been used.
  • Another participant reiterates the importance of the time taken to stop in determining the collision force, referencing a formula for calculating force based on initial and final velocities.

Areas of Agreement / Disagreement

Participants express differing views on the nature of acceleration after an initial force is applied and the relationship between the applied force and collision force. There is no consensus on the exact dynamics of the collision forces, as multiple models and interpretations are presented.

Contextual Notes

Some assumptions about the conditions of motion, such as the absence of resistance and the specifics of the collision scenario, remain unresolved. The discussion also highlights the dependence on definitions and interpretations of force and acceleration.

Miraj Kayastha
Messages
80
Reaction score
0
I have a confusion:
If we push an object of 10 kg with force of 60N once, does it accelerate constantly with 6m/s/s forever neglecting any resistance ?

So, does this mean if this moving object collides with something the maximum force it applies is 60N?
 
Physics news on Phys.org
I probably shouldn't be answering stuff because I am new too. But I'll have a crack at it anyway.

P=mv where p is momentum and momentum is conserved. However you said it was only pushed once with 60N which makes me wonder if it would have a constant acceleration of 6m/s/s. I would have thought it would require a force acting on it to achieve constant acceleration. Otherwise it may have uniform motion of 6 m/s meaning 10kg multiplied by 6 which equals 60N.

In that case yes it would hit something with 60N of force. But I am assuming this is a object in space with no resistance or opposing forces acting on it.
 
Miraj Kayastha said:
I have a confusion:
If we push an object of 10 kg with force of 60N once, does it accelerate constantly with 6m/s/s forever neglecting any resistance ?
No, it accelerates at that rate for as long as the force is applied, and when the force is no longer applied it stops accelerating and coasts along at whatever speed it reached while the force was being applied. In your example, the acceleration is ##\frac{6m}{sec^2}##, so if the force is applied for five seconds, the object will be moving at 30 m/sec.

So, does this mean if this moving object collides with something the maximum force it applies is 60N?
No. The force applied in the collision depends on the deceleration. If our object collides with something very hard and immobile, it might only compress the target by .1 mm before being brought to rest. If our object is moving at 20 meters/sec when it hits and it's stopped cold after covering .1 mm, its average speed during the collision is 10 meters/sec (average of 20 and 0), it takes .00001 seconds to cover that .0001 meters, the deceleration is 2000000 ##\frac{m}{sec^2}##, and the force (which isn't applied for very long - think hammer blow) is 12000000 N.

Repeat this calculation with something soft and squishy, so that it compresses by 10 centimeters, and you'll get a much smaller force.
 
  • Like
Likes   Reactions: 1 person
For your first question, the answer is yes. It will constantly increase its speed but the rate of change of the speed is constant (acceleration is constant).
 
MHR-Love said:
For your first question, the answer is yes. It will constantly increase its speed but the rate of change of the speed is constant (acceleration is constant).

You should read the post immediately before yours.
 
  • Like
Likes   Reactions: 1 person
Yes you are right. I've just read it again. It's a bad thing from me not to read the word "once". In this case, Nugatory's answer is correct.
 
@Nugatory , isn't the force applied is 20000000 and not 12000000 because the mass is 10kg not 6 kg...!
 
  • Like
Likes   Reactions: 1 person
ajayguhan said:
@Nugatory , isn't the force applied is 20000000 and not 12000000 because the mass is 10kg not 6 kg...!

thanks - good catch.
 
Miraj Kayastha said:
So, does this mean if this moving object collides with something the maximum force it applies is 60N?
Collision force is given by the formula

##F=\frac{mv-mu}{t}##

-Where u=Initial velocity ,v= final velocity

For example,Object was traveling at a constant velocity and has the same.
It gets in contact with a wall or something,the force exerted is determined by the time taken for it to stop.
 

Similar threads

  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 35 ·
2
Replies
35
Views
5K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 40 ·
2
Replies
40
Views
4K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 14 ·
Replies
14
Views
1K
  • · Replies 15 ·
Replies
15
Views
4K
  • · Replies 5 ·
Replies
5
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K