Momentum Conservation in Collisions - How to Solve for Resulting Velocity

In summary, the two trucks collided and as a result each truck had a mass of 150 kg and 180 kg. The resultant velocity was 45 m/s and 55 m/s.
  • #1
ilovephysics07
1
0
I'm confused on how to start this Physics problem. Please help me and go through the steps with me.
Thank you.

Two trucks collide. One weighed 1500 Newton and was traveling 45.0 m/s at 105 degrees. The second weighed 1800 Newton and was traveling 27.5 m/s at 55 degrees. Find the resulting velocity of the trucks if they stuck together on impact

Ok so the first step i did was get the mass which is the force (1500) divided by 9.8 m/s^2 and got 150 kg and did the same to truck #2 and got 180 kg.
Because i know we have to use the mass to find the momentum which is force time velocity.

However after that step what i do?
 
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  • #2
The setup will be one of a completely inelastic collision:$$m_{1}v_{1} + m_{2}v_{2} = (m_{1} + m_{2}) v$$This means that the sum of the individual momenta will equal the momentum of the combined masses. However, since this problem is in two dimensions, you need to use the equation twice: once for the x-components of velocity, and again for the y-components.
 
  • #3
Hello lover and welcome to PF. A special welcome, I might add, because the nickname fills us with (false?) pride.

Somehow you managed to evade the template. But your rendering of these toy trucks smacking into one another gives me the impression you've seen it come by. Please use it next time.

Now to business: One of the relevant equations would be F = mg which you used to calculate the m. Decently written exercise: weight as a force. We like that.
Another would be conservation of momentum. You should have learned that momentum is conserved in accidents like this. Momentum is not force times velocity, but mass times velocity. masses you have, velocities you have also. Note that velocities are vectors: they have a magnitude (given) and a direction (also given). All you have to do is add these momentum vectors to get the momentum vector of the stuck-together wreckage, of which you can easily calculate the mass. Divide by mass and voila: the velocity vector !
 

1. What is momentum in physics?

Momentum in physics is a measure of an object's motion, specifically its mass and velocity. It is calculated by multiplying an object's mass by its velocity. In simpler terms, momentum is the quantity of motion an object has.

2. How is momentum conserved in a closed system?

In a closed system, momentum is conserved, meaning it cannot be created or destroyed. This means that the total momentum of all objects in the system before a collision or interaction is equal to the total momentum after the collision or interaction.

3. What is the difference between momentum and velocity?

Momentum and velocity are related but different concepts. Velocity is a measure of an object's speed and direction, while momentum is a measure of an object's motion. Momentum takes into account an object's mass, while velocity does not.

4. How does mass affect momentum?

Mass directly affects momentum, as momentum is calculated by multiplying an object's mass by its velocity. This means that an object with a greater mass will have a greater momentum, assuming the same velocity.

5. Can momentum be transferred between objects?

Yes, momentum can be transferred between objects through collisions or interactions. This is known as the law of conservation of momentum, which states that the total momentum of a closed system remains constant.

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