Question

15kg cat initially traveling +2m/s accelerates at +2m/s2 for 5 seconds how much kinetic energy does it again?

Answer 1

Answer:

A) 1050[J]

Explanation:

First, we must calculate the initial kinetic energy when the cat moves at 2 [m/s].

$E_{1} =0.5*m*v_{o}^{2} \\where:\\m = mass = 15[kg]\\v_{o} = 2[m/s]\\\\therefore\\E_{1} =0.5*15*(2)^{2} \\E_{1}= 30[J]$

Then we can calculate the final velocity with the acceleration and time data that was given.

$v_{f} = v_{o}+a*t\\ v_{f} =2+(2*5)\\v_{f} = 12[m/s]$

And we can calculate the kinetic energy as follows:

$E_{2} =0.5*m*v_{f}^{2} \\E_{2} =0.5*15*(12)^{2} \\E_{2} = 1080[J]$

And now we can calculate the difference in kinetic energy by simply subtracting the values calculated above.

DE = 1080 - 30 = 1050[J]