Question

A 12 kg sled is moving at a speed of 3.0m/s. At which of the following speeds will the sled have four times as much kinetic energy

Answer 1

Given that

m = 12 kg ,

speed (v) = 3 m/s  

kinetic energy ( KE) = 1/2 × m × v²   Joules

                                  = 1/2 × 12 × 3²

                                  = 54 J

If we have the options we can find the speed by keeping the speed in above formula. ( 54 ×  4 =216 J) for the speed of __________m/s