# Find final velocity and kinetic energy lost.

• ScienceGeek24
In summary, the conversation discussed the collision of two masses, m1=6kg and m2=16kg, with velocities of 4 m/s and 3 m/s respectively. The two masses stick together after the collision. Using conservation of momentum, the final velocity of the combined masses can be calculated, as well as the kinetic energy lost in the collision. Equating the initial and final momenta in the x and y directions can help solve for the final velocity.
ScienceGeek24

## Homework Statement

Mass m1=6kg traveling with velocity 4 m/s collides with mass m2=16kg traveling with velocity 3m/s in the direction shown (m2= is at an angle of 60degress). If the two masses stick together, find the final velocity of the combined masses, and the kinetic energy lost.

## Homework Equations

m1v1+m2v2/m1+m2 , 1/2mv^2

## The Attempt at a Solution

I tried equating 1/2mv^2= m1v1+m2v2/m1+m2 i tried finding the momentum and equate it with the KE but is no the right set up. I trying to come up witht he right set up but thisis the lonly thing that is poping in my head. I'm trying to find the velocity of the combined masses but they cannot be the sum of the masses v=2m i don't know what I'm doing. Help?

Hi ScienceGeek24!
ScienceGeek24 said:
I tried equating 1/2mv^2= m1v1+m2v2/m1+m2 i tried finding the momentum and equate it with the KE but is no the right set up.

That makes no sense.

You can't equate energy and momentum, they're completely different.

Use conservation of momentum (it always applies in a collision), in the x and y directions.

Got it! using conservation of momentum found my velocity and with that i just simply the KEf to calculate the subratction of KE total minues KEf for my kinetic energy lost. Thanks!

## 1. What is the formula for finding final velocity?

The formula for finding final velocity is:
Where vf is the final velocity, vi is the initial velocity, a is acceleration, and d is distance traveled.

## 2. How do you calculate kinetic energy lost?

The formula for calculating kinetic energy lost is:
KE lost = 1/2 * m * (vf^2 - vi^2)
Where m is the mass of the object, vf is the final velocity, and vi is the initial velocity.

## 3. Can final velocity be negative?

Yes, final velocity can be negative. This indicates that the object is moving in the opposite direction of its initial velocity.

## 4. What is the unit of measurement for final velocity?

The unit of measurement for final velocity is meters per second (m/s).

## 5. How does kinetic energy lost affect the object's motion?

Kinetic energy lost is the energy that an object loses as it slows down. This decrease in kinetic energy will cause the object to slow down or come to a complete stop, depending on the amount of energy lost. The greater the kinetic energy lost, the greater the change in the object's motion will be.

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