Question

To find the kinetic energy of a baseball when it hits a window, you would need to calculate its mass and velocity, then use the formula KE = 0.5 x mass x velocity^2 to determine the energy it possesses upon impact.

Answer 1

That's correct! To calculate the kinetic energy (KE) of a baseball just before it hits a window, you would use the formula:

\[
KE = 0.5 \times m \times v^2
\]

where:
- \( KE \) is the kinetic energy,
- \( m \) is the mass of the baseball, and
- \( v \) is the velocity of the baseball just before impact.

### Steps to Calculate Kinetic Energy:

1. **Determine the Mass (\( m \))**:
A standard baseball has a mass of approximately 0.145 kg (or 145 grams).

2. **Determine the Velocity (\( v \))**:
You need to measure or estimate the speed of the baseball just before it impacts the window. This can be done with a speed gun or by calculating it if you know the distance and time it took to reach that point.

3. **Plug Values into the Formula**:
After obtaining the mass and velocity, substitute them into the equation to calculate the kinetic energy.

### Example Calculation:
- Let's assume the mass of the baseball is \( 0.145 \) kg, and it is traveling at a velocity of \( 30 \) m/s just before it hits the window.

Using the formula:
\[
KE = 0.5 \times 0.145 \, \text{kg} \times (30 \, \text{m/s})^2
\]
\[
KE = 0.5 \times 0.145 \times 900
\]
\[
KE = 0.5 \times 130.5
\]
\[
KE = 65.25 \, \text{J}
\]

So, the kinetic energy of the baseball upon impact would be approximately \( 65.25 \) joules.