A stationary mass m = 1.3 kg is hanging from a spring of spring constant k = 1200 N/m.You raise the mass a distance of 10 cm above its equilibrium position in a time of 1.4 s.What was the average power expended?
A)0.93 W
B)4.3 W
C)5.2 W
D)8.6 W
E)10.2 W

Question

Quizplus · Accepted Answer

The potential energy stored in the spring is given by:

Us = 1/2 k x^2

where k is the spring constant and x is the displacement from equilibrium position.

When the mass is raised by 10 cm, the displacement is x = 0.1 m. So, the potential energy stored in the spring is:

Us = 1/2 * 1200 N/m * (0.1 m)^2 = 6 J

The work done on the system to raise the mass is equal to the potential energy stored in the spring. So,

W = ΔUs = 6 J

The time taken to raise the mass is t = 1.4 s. The average power expended is given by:

P = W/t

Substituting the values, we get:

P = 6 J / 1.4 s = 4.3 W

Therefore, the answer is C) 5.2 W.

A Stationary Mass M = 1