The speed of the mass is determined as 6.93 m/s.
How to calculate the speed of the mass?
The speed of the mass is calculated by applying the law of conservation of energy as follows;
Gravitational potential energy of the mass = kinetic energy of mass + elastic energy of the spring
mgh = ¹/₂mv² + ¹/₂kx²
where;
- m is the mass
- v is the speed of the mass
- k is the spring constant
- x is the extension of the spring
20 x 9.8 x 0.4 = ¹/₂ x 20 x v² + ¹/₂ x (380) x (0.4²)
78.4 = 10v² + 30.4
10v² = 78.4 - 30.4
10v² = 48
v² = 48 / 10
v² = 4.8
v = √ (4.8)
v = 6.93 m/s