**Example: **

**A block with a mass of 2Kg is sliding on a horizontal frictionless surface with a velocity of 2.5 m/s. The block strikes a spring (K=4×10^3 N/m), Assume the impact is elastic (Both kinetic energy and momentum and conserved)**

**A.) What is the initial kinetic energy of the system?**

**B.) What is the kinetic energy of the system when the spring is compressed to x=1cm?**

**C.) How fast is the block moving at this point?**

**Known**

**Find**

**Draw a Picture**

**Draw two energy states**

**Find energy at these states**

Set the equations equals

energy at state 1 = energy at state 2

KE1=KE2+SE2

Solve for KE2

KE2=KE1-SE2

(6.255)-

6.255-()=KE2=6.05J

Solve for from KE2

KE2=

Solve for