# Conservation of Momentum Problem? Physics help?

A 2110 kg car traveling to the west at 21.2m/s slows down uniformly under a force of

8260 N to the east.

a) How much force would be required to

cause the same acceleration on a car of mass

3250 kg?

Answer in units of N.

b) How far would the car move before stopping?

Answer in units of m.

### 1 Answer

Relevance

- NCSLv 71 month agoFavourite answer
Nothing to do with conservation of momentum. Maybe conservation of energy on part b, but you could instead use kinematics.

a) For the same acceleration, the ratio of force to mass is the same:

F / 3250kg = 8260N / 2110kg → F = 12,723 N (east)

b) By conservation of energy,

½mv² = Fd

½*2110kg*(21.2m/s)² = 8260N * d → d = 57.4 m

By kinematics,

v² = u² + 2ad

substitute a = -F/m and get

0² = 21.2² - 2*(8260/2110)*d

with the same result.

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