- #1

KatlynEdwards

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## Homework Statement

The figure shows a block on a frictionless surface attached to a spring. The block is pulled out to position x_i = 20 cm, then given a "kick" so that it moves to the right with speed v_i. The block then oscillates with an amplitude of 44 cm.

Image of the problem - http://session.masteringphysics.com/problemAsset/1013861/11/jfk.Figure.Q14.21.jpg

What is the oscillation frequency?

What is the total mechanical energy of the oscillator?

What was the initial speed v_i?

## Homework Equations

Hooke's Law

Force = k*change in distance

Frequency - (1/2*pi)*sqrt(k/mass)

Total mechanical energy = potential energy + kinetic energy

Potential energy = 1/2*k*Amplitude^2

Kinetic energy = 1/2 * mass*v_max^2

## The Attempt at a Solution

F=k*change in x

20 = k*0.2

k = 100

Frequency= (1/2pi) * sqrt(k/m)

Frequency=(1/2pi) * sqrt (100/.5)

Frequency=2.251 Hz

For some reason the answer is 1.0 Hz but I can't figure out what I did wrong. Once I figure this one out I can move onto the next two.

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