Homework Help: What is the speed of the block when the spring has been compressed...

A block with a mass of 0.148kg is traveling at 8.4m/s on a horizontal,frictionless surface when it hits a spring with a spring constant of 722 N/m. What is the compression of the spring when the block has slowed to 3.9 m/s?What is the speed of the block when the spring has been compressed by 0.049m?

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