Answer:
480 Joules
Step-by-step explanation:
Start by listing out your variables.
Mass (m) = 120kg
Initial Velocity (Vi) = 4.5 m/s
Final Velocity (Vf) = 3.5 m/s
Kinetic Energy (KE) = ?
After looking at a Formula Chart, we can determine which equation we can use based on what we need to solve and what variables we have.
In this case, we have the mass, final velocity, and initial velocity, and we're trying to determine the kinetic energy.
With this information, we can use the equation KE = ½ mv^2.
We'll start by plugging in the variables for the initial amount of kinetic energy.
So for KE = ½ mv^2,
KE = ½ (120) (4.5) ^2
KE = 1215
Next, we'll plug in the variables for the final amount of kinetic energy.
So for KE = ½ mv^2,
KE = ½ (120) (3.5) ^2
KE = 735
Lastly, just determine the difference between the final and initial kinetic energy.
1215 - 735 = 480
480 Joules of Kinetic Energy was lost.