Conservation of Momentum Problem

Click For Summary
SUMMARY

The discussion centers on a physics problem regarding the conservation of momentum when two objects, A and B, are subjected to the same horizontal force over the same time period on a frictionless surface. The correct conclusion is that both objects have the same momentum after the force is applied, as indicated by option (c). This is derived from the principle that the change in momentum (delta_p) is equal for both objects due to the identical force application, despite their differing masses. The initial momentum of both objects is zero, confirming that their final momenta must also be equal.

PREREQUISITES
  • Understanding of Newton's Second Law (F = ma)
  • Familiarity with the concept of momentum (p = mv)
  • Knowledge of the integral calculus as it applies to force and momentum changes (delta_p = integral(F dt))
  • Basic principles of physics regarding frictionless surfaces and initial conditions
NEXT STEPS
  • Study the implications of Newton's Second Law in various scenarios
  • Explore the relationship between force, mass, and acceleration in-depth
  • Investigate the concept of impulse and its effect on momentum
  • Learn about conservation laws in physics, particularly momentum conservation in collisions
USEFUL FOR

Students studying physics, educators teaching mechanics, and anyone interested in understanding the principles of momentum and force interactions in a frictionless environment.

Avefan
Messages
1
Reaction score
0

Homework Statement


The same horizontal force is applied separately to two objects initially at rest on a horizontal, frictionless surface. Object A has less mass than object B. In each case the force is applied for the same length of time. Which of the following statements is true after the push?

(a) Object A has greater momentum than object B.
(b) Object B has greater momentum than object A.
(c) Object A has the same momentum as object B.
(d) Object A has the same kinetic energy as object B.
(e) Both objects have no momentum.

Homework Equations


p = mv
delta_p = integral(F dt)

The Attempt at a Solution


The answer key solution to this problems is option c with the explanation that "since the both objects are given the same force over the same period of time, F = dp/dt , delta_pa = delta_pb."
However, why is delta_p(change in momentum) the same as momentum and why isn't option (b) a plausible answer?
 
Physics news on Phys.org
Avefan said:

Homework Statement


The same horizontal force is applied separately to two objects initially at rest on a horizontal, frictionless surface. Object A has less mass than object B. In each case the force is applied for the same length of time. Which of the following statements is true after the push?

(a) Object A has greater momentum than object B.
(b) Object B has greater momentum than object A.
(c) Object A has the same momentum as object B.
(d) Object A has the same kinetic energy as object B.
(e) Both objects have no momentum.

Homework Equations


p = mv
delta_p = integral(F dt)

The Attempt at a Solution


The answer key solution to this problems is option c with the explanation that "since the both objects are given the same force over the same period of time, F = dp/dt , delta_pa = delta_pb."
However, why is delta_p(change in momentum) the same as momentum and why isn't option (b) a plausible answer?
Both objects start at rest so the initial momentum of both is 0 (i.e. initial_p=0). So at any time, delta_p = current_p - initial_p = current_p - 0 = current_p
Of course, (c) contradicts (b), so (b) can not be true.
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
2K
Replies
2
Views
1K
  • · Replies 17 ·
Replies
17
Views
1K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 7 ·
Replies
7
Views
1K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 19 ·
Replies
19
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 13 ·
Replies
13
Views
1K