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## Homework Statement

A 1.40 kg block slides with a speed of 0.885 m/s on a frictionless horizontal surface until it encounters a spring with a force constant of 637 N/m . The block comes to rest after compressing the spring 4.15 cm.

**Part A**

Find the spring potential energy, U, the kinetic energy of the block, K, and the total mechanical energy of the system, E, for compressions of 0 cm.

**Part B**

Find the spring potential energy, U, the kinetic energy of the block, K, and the total mechanical energy of the system, E, for compressions of 1.00 cm.

**Part C**

Find the spring potential energy, U, the kinetic energy of the block, K, and the total mechanical energy of the system, E, for compressions of 2.00 cm.

**Part D**

Find the spring potential energy, U, the kinetic energy of the block, K, and the total mechanical energy of the system, E, for compressions of 3.00 cm.

**Part E**

Find the spring potential energy, U, the kinetic energy of the block, K, and the total mechanical energy of the system, E, for compressions of 4.00 cm.

## Homework Equations

Potential energy= 1/2Kx

^{2}

Kinetic energy=1/2mv

^{2}

Mechanical energy=KE+PE

## The Attempt at a Solution

I got the first answer correct using these equations. However, when I use these equations for part B I get them wrong. For example, this is what I did.

part B) PE=(.5)(.01m)(.0415m)

^{2}=8.6x10

^{-6}J

KE= (.5)(1.40kg)(.885m/s)

^{2}= .548 J

ME= .548J+8.6x10

^{-6}= .548 J

I don't know what I am doing wrong if someone can please explain I would appreciate it! Also, I have seen in other examples that the KE is supposed to change with each compression. How? if the mass and the velocity remain the same?