# Formula involving the change in a kinetic energy

1. Apr 16, 2009

### electrical_ck

I'm looking for a formula involving the change in a kinetic energy, I have a 120 N force applied at an angle of 30 degrees above the horizontal to a 4kg box. The box moves a horizontal distance of 8 meters. The change in the kinetic energy of the box is:

Just looking for a formula to figure this one out

2. Apr 16, 2009

### rock.freak667

The work done by the force on the box=Change in kinetic energy of the box.

3. Apr 18, 2009

### Novolks

Hi,...What equations do you have for work? Calculate the vector components of the 120N force. This will simplify the problem for you.

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4. Apr 18, 2009

### Pengwuino

If you assume the initial velocity is 0, you know that the final energy of the box is E = K + V, K being the kinetic energy and V being the potential. If gravity is involved, your potential V is mgh. If not, it's 0. You also know that your total energy, or the work done to the box, is equal to $$F \cdot d\overrightarrow x$$. Break down the force into its components to determine the work done.

Last edited: Apr 18, 2009