Question

A ring is attached at the center of the underside of a trampoline. A sneaky teenager crawls under the trampoline and uses the ring to pull the trampoline slowly down while his 79-kg mother is sleeping on it. When he releases the trampoline, she is launched upward. As she passes through the position at which she was before her son stretched the trampoline, her speed is 2.5 m/s .

Answer 1

Answer:

Explanation:

Given

Mass of mother $m=79\ kg$

Mother is released with a speed of $v=2.5\ m/s$

Assuming we need to find elastic Potential energy stored in Trampoline

Kinetic energy acquired  by Mother comes from Elastic Potential Energy stored in the spring

I.e. Elastic Potential Energy=Kinetic Energy of mother

$\frac{1}{2}kx^2=\frac{1}{2}mv^2$

$E=\frac{1}{2}\times 79\times 2.5^2=246.875\ J$

So 246.875 J of Energy is stored in the trampoline as he pull the ring