Question

A car is driving at 20mph and has a kinetic energy of 1000J. If the car triples its speed, how much KE will it have?

Answer 1

@agent0smith

Answer 2

@IrishBoy123

Answer 3

what is the formula for KE?? d'ya know?

Answer 4

I believe it is \[\frac{ 1 }{ 2 }*mv^2\]

Answer 5

yes!

so "initially" the car has KE:

\(T_1 = \frac{1}{2} m v^2\)

then it speeds up such that \(v \to 3v\)

so it ends up with KE

\(T_2 = \frac{1}{2}m (3 v)^2\)

follow?

Answer 6

Yup!

Answer 7

So

\(\Large T_2 = \frac{1}{2}m (3 v)^2 = 9 \times \frac{1}{2}m v^2 = 9 \times ?\)

Answer 8

put it another way

we have concluded that

\(\Large T_2 = ?? \times T_1\)

Answer 9

^