# physics

posted by .

A 1000 kg car is rolling down the street at 2.5 m/s. How fast would a 2500 kg car have to collide into it in order to bring it to rest (0 m/s)?

• physics -

initial momentum = 1000*2.5 + 2500 * v = final momentum = 0

v = - 2500/2500 = -1 m/s

• physics -

Use momentum conservation and assume the cars stick together.
1000*2.5 - (2500)*V = 0
V = 1.0 m/s

## Similar Questions

1. ### Physics

A vacant, 1560 kg car begins from rest and rolls 46 meters down an inclined plateau before rolling off the edge and crashing into the sea below. The plateau is at a constant downward angle of 12.4 degrees with the horizontal. The coefficient …
2. ### Physics

A 1100 kg car is moving toward the north along a straight road at a speed of 20.0 m/s. The driver applies the brakes and the car comes to rest in a distance of 140 m. (a) If the road is completely level, what is the constant force …
3. ### Physics

A 1100 kg car is moving toward the north along a straight road at a speed of 20.0 m/s. The driver applies the brakes and the car comes to rest in a distance of 140 m. (a) If the road is completely level, what is the constant force …
4. ### physics

A car is moving down a street at 51 km/h. A child suddenly runs into the street. If it takes the driver 0.97 s to react and apply the brakes, how many meters will the car have moved before it begins to slow down?
5. ### Physics

The brakes on a parked car fall and it accelerates at a constant rate, rolling into a lamp post down the hill. the car reaches a velocity of 4.3m/s by the time it smashes into the lamp post. The time between the brakes failing and …
6. ### Physics

A 1000-kg car is driving toward the north along a straight road at a speed of 20.0 m/s. The driver applies the brakes and the car comes to a rest in a distance of 140 m. What is the constant force applied to the car to bring it to …
7. ### physics

a car is moving down a street at 55km/h.A child suddenly runs into the street. If it takes a driver 0.75s to react and apply the brakes, how many meters will the car have moved before it begins to slow down?
8. ### physics

A car is moving down a street at 51 km/h. A child suddenly runs into the street. If it takes the driver 0.62 s to react and apply the brakes, how many meters will the car have moved before it begins to slow down?
9. ### physics

a 1,000 kg car is rolling down the street at 2.5 m/s. How fast would a 2,500 kg car have to collide into it in order to bring it to rest(0 m/s) ?
10. ### Physics

A car is moving down a street at 67 km/h. A child suddenly runs into the street. If it takes the driver 1.26 s to react and apply the brakes, how many meters will the car have moved before it begins to slow down?

More Similar Questions