Momentum/Impulse [Final Velocity]

[silverduelist]

Homework Statement

"A truck weighs four times as much as a car, If the truck coasts into the car at 12 km/h and they stick together, what is their final velocity."

Homework Equations

Change in momentum a = change in momentum b
OR
m1v1 = m2v2
OR
(delta)P system = 0

The Attempt at a Solution

I HAVE NO IDEA. SRSLY.

 

[Hootenanny]

Homework Statement

"A truck weighs four times as much as a car, If the truck coasts into the car at 12 km/h and they stick together, what is their final velocity."

Homework Equations

Change in momentum a = change in momentum b
OR
m1v1 = m2v2
OR
(delta)P system = 0

The Attempt at a Solution

I HAVE NO IDEA. SRSLY.

Welcome to Physics forums.

As you have correctly surmised, momentum is conserved in this case (since there are no net external forces acting). All three of your relevant equations are equivalent, so how about trying to apply one of them to this problem?

 

[thomate1]

I understand that momentum and impulse are important concepts in physics that describe the motion of objects. In this situation, we can use the equation Change in momentum a = change in momentum b or m1v1 = m2v2 to solve for the final velocity of the truck and car after they collide.

Since the truck weighs four times as much as the car, we can assign the truck's mass as 4m and the car's mass as m. We also know that the truck's initial velocity is 12 km/h and the car's initial velocity is 0 km/h since it is at rest.

Using the equation, we can set up the following equation:

(4m)(12 km/h) = (m + 4m)v2

Simplifying the equation, we get:

48m km/h = 5m v2

Dividing both sides by 5m, we get:

9.6 km/h = v2

Therefore, the final velocity of the combined truck and car is 9.6 km/h. This means that the two objects will continue to move together at a speed of 9.6 km/h after the collision.

In conclusion, by using the principle of conservation of momentum, we can determine the final velocity of the truck and car after they collide and stick together. This is just one application of momentum and impulse in the real world, and it is important to understand these concepts in order to accurately describe and predict the motion of objects.