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Select the correct answer.

What is the velocity of a ball falling with 100 joules of kinetic energy and a mass of 2 kilograms? Use the formula [tex]V=\sqrt{\frac{2 KE}{m}}[/tex].

A. [tex]3 \, \text{m/s}[/tex]
B. [tex]5 \, \text{m/s}[/tex]
C. [tex]7 \, \text{m/s}[/tex]
D. [tex]8 \, \text{m/s}[/tex]
E. [tex]10 \, \text{m/s}[/tex]



Answer :

To find the velocity of the ball given its kinetic energy and mass, we use the formula for kinetic energy in terms of velocity:

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

where:
- [tex]\( KE \)[/tex] is the kinetic energy,
- [tex]\( m \)[/tex] is the mass,
- [tex]\( v \)[/tex] is the velocity.

We are given:
- [tex]\( KE = 100 \)[/tex] joules,
- [tex]\( m = 2 \)[/tex] kilograms.

First, let's solve for [tex]\( v \)[/tex] by isolating it on one side of the equation. From the formula [tex]\( KE = \frac{1}{2} m v^2 \)[/tex]:

1. Multiply both sides by 2 to eliminate the fraction:

[tex]\[ 2 \cdot KE = m v^2 \][/tex]

This simplifies to:

[tex]\[ 200 = 2 v^2 \][/tex]

2. Divide both sides by [tex]\( m \)[/tex] to solve for [tex]\( v^2 \)[/tex]:

[tex]\[ \frac{200}{2} = v^2 \][/tex]

This simplifies to:

[tex]\[ 100 = v^2 \][/tex]

3. Finally, take the square root of both sides to solve for [tex]\( v \)[/tex]:

[tex]\[ v = \sqrt{100} \][/tex]

[tex]\[ v = 10 \, \text{m/s} \][/tex]

Therefore, the correct answer is:

E. [tex]\( 10 \, \text{m/s} \)[/tex]