Finding the hange in inetic energy

[sylavel]

Homework Statement

A 1609 kg car has a speed of 11.9 m/s when it hits a tree. The tree doesn't move and the car comes to rest.
Find the change in kinetic energy of the car. Answer in units of J.

Homework Equations

KE=1/2mv^2

The Attempt at a Solution

Okay so like I am not completely sure where to go here...
I started out in finding the kinetic energy
KE=1/2(1609)(11.9)^2=113925.245
Any help would be super awesome.

 

[LowlyPion]

Homework Statement

A 1609 kg car has a speed of 11.9 m/s when it hits a tree. The tree doesn't move and the car comes to rest.
Find the change in kinetic energy of the car. Answer in units of J.

Homework Equations

KE=1/2mv^2

The Attempt at a Solution

Okay so like I am not completely sure where to go here...
I started out in finding the kinetic energy
KE=1/2(1609)(11.9)^2=113925.245
Any help would be super awesome.

OK You found the Kinetic energy for before impact.

What is the KE after impact? What is v?

What is the difference?

 

[thomate1]

Thanks!

I would like to clarify a few things before providing a response. Firstly, it is important to state the unit of mass and velocity in the equation for kinetic energy, which is KE=1/2mv^2. In this case, the mass would be in kilograms (kg) and velocity in meters per second (m/s). Secondly, it is important to use consistent units throughout the calculation to ensure accurate results.

Now, to answer the question, we can use the equation for change in kinetic energy, which is given by ΔKE= KEfinal - KEinitial. In this case, the car comes to rest after hitting the tree, so the final kinetic energy would be zero. Therefore, the change in kinetic energy of the car would be:

ΔKE = 0 - 113925.245 J = -113925.245 J

Note that the negative sign indicates that there is a decrease in kinetic energy, as the car's initial kinetic energy was greater than zero. I hope this helps clarify the concept of change in kinetic energy for you.