Question

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

A. 1050J
B. 30J
C. 500J
D. 1080J

Answer 1

A) 1050[J]

Step-by-step 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]