Answer:
0.8 J
Explanation:
According to the law of conservation of energy, all the elastic potential energy stored in the spring is converted into kinetic energy of the dart:
[tex]U=K[/tex]
where we have
[tex]U=\frac{1}{2}kx^2[/tex] is the elastic potential energy of the spring, where k is the spring constant and x is the compression/stretching of the spring
[tex]K=\frac{1}{2}mv^2[/tex] is the kinetic energy of the dart, where m is the mass and v is the speed
The elastic potential energy of the spring is equal to the work done in compressing it, so
U = 0.8 J
and according to the law of conservation of energy, the kinetic energy gained by the dart is exactly equal to the potential energy stored in the spring:
K = U =0.8 J
