Answer:
Katelyn is right
Explanation:
Her doubling of the speed of the watermelon will make a bigger increase in the kinetic energy. The kinetic energy of Katelyn's watermelon was 100 Joules at 10 m/s and 400 Joules at 20 m/sec. The kinetic energy of Robkins's 2 kg watermelon was 100 Joules and the kinetic energy of his 4kg watermelon was 200 Joules.
The kinetic energy of Katelyn's watermelon increased by 300 Joules (400 Joules - 100 Joules). The kinetic energy of Robin's watermelons increased by 100 Joules (2200 Joules - 100 Joules)
I found it on the internet
Hope that helps dude