Finding mechanical energy of simple harmonic oscilator

[Dalip Saini]

Homework Statement

A simple harmonic oscillator consists of a block of mass 45 g attached to a spring of spring constant 240 N/m, oscillating on a frictionless surface. If the block is displaced 3.5 cm from its equilibrium position and released with an initial velocity of 2.5 m/s, what is its total energy?

• A
  
  0.15 J
• B
  
  The total energy varies during each cycle of oscillation.
• C
  
  0.20 J
• D
  
  0.29 J
• E
  
  0.14 J

Homework Equations

E = 0.5kx^2+0.5mv^2

The Attempt at a Solution

I plugged in the values into the formula and I got 0.14J but the answer is 0.29J

 

[SammyS]

Homework Statement

A simple harmonic oscillator consists of a block of mass 45 g attached to a spring of spring constant 240 N/m, oscillating on a frictionless surface. If the block is displaced 3.5 cm from its equilibrium position and released with an initial velocity of 2.5 m/s, what is its total energy?

• A
  
  0.15 J
• B
  
  The total energy varies during each cycle of oscillation.
• C
  
  0.20 J
• D
  
  0.29 J
• E
  
  0.14 J

Homework Equations

E = 0.5kx^2+0.5mv^2

The Attempt at a Solution

I plugged in the values into the formula and I got 0.14J but the answer is 0.29J

What values did you plug into the formula?

 

[Dalip Saini]

k=240 N/m
x=0.035m
m=0.045
v = 2.5 m/s

 

[Dalip Saini]

Actually I just plugged in the values again and I got the answer. Sorry about that