Physics · Forces and Motion
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If a force of 12 N acts on a car and changes its momentum from 36 kgm/sec to 60 kgm/sec, the time during which this change occurs will be
- A
24 sec
- B
2 sec
- C
12 sec
- D
8 sec
To solve this problem, use the impulse-momentum theorem, which states that the impulse (force multiplied by time) is equal to the change in momentum. The formula is:
F×t = mvf - mvi
Substitute the given values: F = 12 N, mvf = 60 kgm/s, and mvi = 36 kgm/s.
Therefore, t = (60 kgm/s - 36 kgm/s) / 12 N = 24 kgm/s / 12 N = 2 sec.
This means the correct time interval is 2 seconds.
Options 24 sec, 12 sec, and 8 sec are incorrect because they result from errors in dividing the change in momentum by the force.
The calculation is incorrect. The change in momentum is not divided correctly by the force.
This is the correct answer. The change in momentum is 24 kgm/s, and when divided by the force of 12 N, the time is correctly calculated as 2 sec.
The calculation is incorrect. Ensure you divide the change in momentum by the force correctly.
The calculation is incorrect. Double-check your division of the change in momentum by the force.
Tagged under Physics · Forces and Motion · 2010