# Homework Help: Finding initial kinetic energy

1. Jan 29, 2012

### DPXJube

1. The problem statement, all variables and given/known data
A student throws 0.22kg rock horizontally at 20.0m/s from 10.0m above the ground. Ignore air resistance.

Find the initial kinetic energy of the rock

2. Relevant equations
Ek = mv^2/2

3. The attempt at a solution
This sounds INCREDIBLY easy and every shape or form
Simplying plugging in what I know

Ek =(0.22)(20.0)^2/2

Get's me the answer of 9.68
However APPARENTLY that's the wrong answer
The answer that I'm given is 44J
How is this possible? I must have gone completly off track somewhere.

2. Jan 29, 2012

### Staff: Mentor

Check your arithmetic. Pay careful attention to the order of operations.

3. Jan 29, 2012

### PeterO

Your (red) statement is correct - if clumsily written - it would appear the only problem is when you start entering the numbers into your calculator - not that you should need one for that calculation.

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