Answer:
2.5 joules
Step-by-step explanation:
The amount of energy stored in a spring can be calculated using the formula:
E = 1/2 kx^2
where E is the energy stored, k is the spring constant, and x is the displacement of the spring from its equilibrium position.
In this case, the spring constant is 20 N/m and the displacement is 0.5 m (since the spring is compressed). Plugging these values into the formula, we get:
E = 1/2 * 20 N/m * (0.5 m)^2 = 2.5 J
Therefore, the amount of energy stored in the spring is 2.5 joules.