Explanation:
When spring is used to shoot an arrow, the Elastic Potential Energy is converted into Kinetic Energy.
The efficiency of Spring Toy = 69%
According to Conservation of Energy :
P. E. = K. E.
NOW,
69% of P. E. = m * v^2 / 2
[tex]P.E. = \frac{0.0342 \times 5.5 \times 5.5}{2 \times 0.69} = 0.75J[/tex]