- #1

Jngo22

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## Homework Statement

A block of mass m1 = 2 kg slides along a frictionless table with speed 10 m/s. Directly in front of it, and moving in the same direction with a speed of 3 m/s is a block of mass m2 = 5kg. A massless spring with spring constant k = 1120 N/m is attached to the second block. The spring is compressed a maximum amount x. What is the value of x?

## Homework Equations

m1v1 + m2v2 = m1vf1 + m2vf2

KEi = KEf + 1/2kx^2

## The Attempt at a Solution

I knew that there would be a maximum compression of the spring when the first block has velocity = 0 m/s. I used cons. of momentum :

(2 kg)(10 m/s) + (5 kg)(3 m/s) = (5 kg)(Vf) to find Vf = 7 m/s

then used cons. of energy:

(0.5)(5 kg)(7 m/s)^2 = 1/2(1120)x^2

and got x = 0.4677 m

but the correct answer is 0.250 m

can anyone help me find the correct answer