# Physics

posted by .

A 821-kg car stopped at an intersection is rear-ended by a 1810-kg truck moving with a speed of 11.5 m/s. If the car was in neutral and its brakes were off, so that the collision is approximately elastic, find the final speed of both vehicles after the collision.

• Physics -

Use the eqn:
v1'=v1*(m1-m2)/(m1+m2)
M2=neutral car, its v2=0 since its at rest.
m1=truck, v1=11.5.
Then, once you have v1' you can sub it into m1v1+m2v2=m1v1'+m2v2' and find v2'.
The first eqn is a special eqn only to be used when v2=0 and the collision is completely elastic. NEVER under anyother circumstances. They are specialy derived for solely this case.

• Physics -

Vf2=(m1+m2)(Vo1)/m1
m1=truck; m2=car; Vo1=initial speed of truck.

mo1Vo1=mf1Vf1+mf2Vf2; substitute Vf2 to find Vf1

## Similar Questions

1. ### physics

A delivery truck with a mass of 1700 kg is stopped in the street w/o its brakes on, when a small car hits it from behind. The car has a mass of 650 kg, and is traveling at 3.7m/s immediately before it hits the truck. Both the car and …
2. ### Physics

A 821-kg car stopped at an intersection is rear-ended by a 1810-kg truck moving with a speed of 11.5 m/s. If the car was in neutral and its brakes were off, so that the collision is approximately elastic, find the final speed of both …
3. ### physics

A 1093 kg van, stopped at a traffic light, is hit directly in the rear by a 715 kg car traveling with a velocity of +2.38 m/s. Assume that the transmission of the van is in neutral, the brakes are not being applied, and the collision …

1)A 1180-kg van, stopped at a traffic light, is hit directly in the rear by a 753-kg car traveling with a velocity of +1.81 m/s. Assume that the transmission of the van is in neutral, the brakes are not being applied, and the collision …

1)A 1180-kg van, stopped at a traffic light, is hit directly in the rear by a 753-kg car traveling with a velocity of +1.81 m/s. Assume that the transmission of the van is in neutral, the brakes are not being applied, and the collision …
6. ### physics

A 601-kg car stopped at an intersection is rear-ended by a 1660-kg truck moving with a speed of 14.5 m/s. If the car was in neutral and its brakes were off, so that the collision is approximately elastic, find the final speed of both …
7. ### physics

A 853-kg car stopped at an intersection is rear-ended by a 1450-kg truck moving with a speed of 16.0 m/s. If the car was in neutral and its brakes were off, so that the collision is approximately elastic, find the final speed of both …
8. ### physics

A car with a mass of 980 kg is initially traveling east toward an intersection with a speed of vc = 18.9 m/s and a 1500 kg pickup is traveling north toward the same intersection. The car and truck collide at the intersection and stick …
9. ### Physics

A 700-kg car stopped at an intersection is rear-ended by a 1710-kg truck moving with a speed of 16.0m/s . 1) If the car was in neutral and its brakes were off, so that the collision is approximately elastic, find the final speed of …
10. ### physics

A 1075 kg van, stopped at a traffic light, is hit directly in the rear by a 705 kg car traveling with a velocity of +2.06 m/s. Assume that the transmission of the van is in neutral, the brakes are not being applied, and the collision …

More Similar Questions