Answer:
He needs to increase the spring constant by a factor of 11.2
Explanation:
Given the present spring constant of k = 55N/m and stretching distance of x = 0.235m, he must make a slingshot of new spring constant if he must achieve his goal of aiming for 17J slingshot.
E = 1/2×kx²
k= 2E /x² = 2×17/(0.235)² = 34/0.0552 = 616N/m
This new value for I compare to the old one is 616/55 = 11.2
So the new slingshot must have a spring constant 11.2 time as great as the former one.