# Motion equation

posted by
**Fred**
.

I assume that is 5.5 m/s, the initial velocity.

Ok, assuming that, then you know the initial KEnergy; 1/2 .62 (5.5)^2 joules.

At the max height, the KE you are given is KE from horizontal motion. So subtract that amount (2.3J) from the initial KE, and you have then the KE that can go into vertical motion. From that, it is easy:

KE available for vertical motion=PE at top, where PEnergy at the top is mass*g*height and you solve for height.

In answering a question such as this one... you have the total PE = 7.1 J ..

Do you then divide this by mass 0.62 kg multiplied by 9.8 ms or by 9.8 squared ??? If it is 9.8 squared why is this so ????

Why does this mass have KE at top ??? should this not be 0 (zero) ???

Just a little confused...

Thanks

Fred

If you know the increase in PE, having derived if from the KE available from vertical motion, then divide PE by m*g to get the height increase. Joules divided by (kg m/s^2) equals meters

Thank you