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What's the kinetic energy of the object? Use [tex]KE = \frac{1}{2} mv^2[/tex].

Erica is competing in the shot put event at a track meet. She hurls a shot with a mass of 4 kilograms at a speed of 9 meters/second. The shot's kinetic energy is [tex]\boxed{\square}[/tex] joules.


Sagot :

To calculate the kinetic energy of the shot, we use the formula for kinetic energy:

[tex]\[ KE = \frac{1}{2} m v^2 \][/tex]

where
[tex]\( m \)[/tex] is the mass of the object,
[tex]\( v \)[/tex] is the velocity of the object.

Given:
[tex]\[ m = 4 \, \text{kg} \][/tex]
[tex]\[ v = 9 \, \text{m/s} \][/tex]

Now, substitute the given values into the formula:

[tex]\[ KE = \frac{1}{2} \times 4 \, \text{kg} \times (9 \, \text{m/s})^2 \][/tex]

First, calculate [tex]\( (9 \, \text{m/s})^2 \)[/tex]:

[tex]\[ 9 \, \text{m/s} \times 9 \, \text{m/s} = 81 \, \text{m}^2/\text{s}^2 \][/tex]

Next, multiply this result by the mass:

[tex]\[ 4 \, \text{kg} \times 81 \, \text{m}^2/\text{s}^2 = 324 \, \text{kg} \cdot \text{m}^2/\text{s}^2 \][/tex]

Finally, multiply by [tex]\( \frac{1}{2} \)[/tex]:

[tex]\[ \frac{1}{2} \times 324 \, \text{kg} \cdot \text{m}^2/\text{s}^2 = 162 \, \text{J} \][/tex]

Therefore, the kinetic energy of the shot is:

[tex]\[ \boxed{162} \, \text{joules} \][/tex]