# Total energy of an object.

## Homework Statement

If a question asks to calculate total energy of an object that does have a horizontal velocity (constant, air resistance ignored), and it is at it's highest point so it's vertical velocity is zero.

I need to know how you'd calculate the total energy of this object.

Let's take mass as 5kg. And a highest point of 3m. Horizontal velocity of 2m/s. (I just made them up).

## Homework Equations

Potential energy = mgΔh
Kinetic energy = 0.5mv^2

## The Attempt at a Solution

Pe= 5*9.81*3 = 147.15J
Ke= 5*2^2= 20/2 = 10J

10+147.15= 157.15J

I was just wondering if I am not leaving anything out, or if I'm even doing it correct! Thanks

tiny-tim
Homework Helper
Hi Sixty3 (try using the X2 tag just above the Reply box )
Let's take mass as 5kg. And a highest point of 3m. Horizontal velocity of 2m/s. (I just made them up).

Pe= 5*9.81*3 = 147.15J
Ke= 5*2^2= 20/2 = 10J

10+147.15= 157.15J

I was just wondering if I am not leaving anything out, or if I'm even doing it correct! Thanks

Yes, that's fine …

at launch, and when on return to the ground, its KE is 157.15J.

(btw, we normally put a capital 'E' in KE and PE )