Does Equal Force Result in Equal Momentum for Different Masses?

  • Thread starter Thread starter blackout85
  • Start date Start date
  • Tags Tags
    Momentum
AI Thread Summary
Equal forces applied to two bodies of different masses for the same duration result in equal momentum, as momentum before and after the force application must remain constant. The larger mass does not have greater momentum; both bodies will have the same momentum after the forces are removed. In the second scenario, the impulse experienced by a 0.2kg rubber ball dropped from a height is calculated correctly, with the change in momentum equating to 10 upward. The correct calculation for impulse is 0.2 times the rebound velocity minus 0.2 times the impact velocity, confirming the upward direction. Overall, the concepts of impulse and momentum are applied correctly in both cases discussed.
blackout85
Messages
27
Reaction score
1
Please check over my work

Two bodies of unequal mass, placed at rest on a frictionless surface, are acted on by an equal horizontal forces for equal times. Just after the forces are removed, the body of greater mass will have:
The body of greater mass will have the the greater speed, the greater acceleration, the smaller momentum, the greater momentum, or the same amount as the other body.

Would the answer be the larger body would have the same amount amount of momentum as the other body because P(before)=P(after). The momentum would have to come out the same in order for that to be right.

second question:

A 0.2kg rubber ball is dropped from the window of a building. It strikes the sidewalk below at 30m/s and rebounds up at 20m/s. The impulse during the collision would be:

my work:
0.2 (-30m/s) - 0.2 (20m/s) = 10 upward

Please let me know if I am on the right track and let me know where I might have gone wrong:redface:
 
Physics news on Phys.org
blackout85 said:
Would the answer be the larger body would have the same amount amount of momentum as the other body because P(before)=P(after). The momentum would have to come out the same in order for that to be right.

Yes, but you should use the fact that the impulse of the force equals the change of momentum, and since the impulse is equal for both bodies, you have F*t = m1v1 = m2v2.

blackout85 said:
A 0.2kg rubber ball is dropped from the window of a building. It strikes the sidewalk below at 30m/s and rebounds up at 20m/s. The impulse during the collision would be:

my work:
0.2 (-30m/s) - 0.2 (20m/s) = 10 upward

Please let me know if I am on the right track and let me know where I might have gone wrong:redface:

Looks good.

Edit: the change in momentum (i.e. the impulse) should actually be: 0.2\cdot 20\vec{j}-0.2\cdot(-30)\vec{j}=10\vec{j}, which means 10 upwards.
 
Last edited:
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
Thread 'Voltmeter readings for this circuit with switches'
TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...
Thread 'Trying to understand the logic behind adding vectors with an angle between them'
My initial calculation was to subtract V1 from V2 to show that from the perspective of the second aircraft the first one is -300km/h. So i checked with ChatGPT and it said I cant just subtract them because I have an angle between them. So I dont understand the reasoning of it. Like why should a velocity be dependent on an angle? I was thinking about how it would look like if the planes where parallel to each other, and then how it look like if one is turning away and I dont see it. Since...
Back
Top