Answered

An object has a velocity of [tex]$8 \, \text{m/s}$[/tex] and a kinetic energy of 480 J. What is the mass of the object?

(Formula: [tex]KE = \frac{1}{2} mv^2[/tex])

A. 7.5 kg
B. 15 kg
C. 60 kg
D. 120 kg



Answer :

To determine the mass of the object, we can use the kinetic energy formula:

[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.

Given:
[tex]\[ KE = 480 \, \text{J} \][/tex]
[tex]\[ v = 8 \, \text{m/s} \][/tex]

We need to solve for [tex]\( m \)[/tex]. Let's rearrange the formula to isolate [tex]\( m \)[/tex]:
[tex]\[ KE = \frac{1}{2} m v^2 \][/tex]

Multiply both sides of the equation by 2 to get rid of the fraction:
[tex]\[ 2 \times KE = m \times v^2 \][/tex]

[tex]\[ 2 \times 480 = m \times (8)^2 \][/tex]

Which simplifies to:
[tex]\[ 960 = m \times 64 \][/tex]

Now, solve for [tex]\( m \)[/tex] by dividing both sides by 64:
[tex]\[ m = \frac{960}{64} \][/tex]

[tex]\[ m = 15 \, \text{kg} \][/tex]

So the mass of the object is:
[tex]\[ \boxed{15 \, \text{kg}} \][/tex]

Therefore, the correct answer is 15 kg.