Given the equation: $\frac{1}{2}(0.20\mathrm{~kg})\left(v_{1x}\right)^2+\frac{1}{2}(3.5\mathrm{~N}/\mathrm{m})(0\mathrm{~m})^2=\frac{1}{2}(0.20\mathrm{~kg})(0\mathrm{~m}/\mathrm{s})^2+\frac{1}{2}(3.5\mathrm{~N}/\mathrm{m})\left(\Delta x_2\right)^2$


Which of the following problem statements is valid for this equation?

• A. A 100 g ball of putty traveling at 3.0 m/s strikes and sticks to another 100 g ball of putty at rest on a frictionless surface. The combined balls then compress a horizontal spring with a spring constant of 3.5 N/m. The other end of the spring is firmly anchored to a fixed post on the surface. How far will the spring compress?
• B. A 100 g ball of putty traveling at 3.0 m/s strikes and bounces off another 100 g ball of putty at rest on a frictionless surface. The first ball then compresses a horizontal spring with a spring constant of 3.5 N/m. The other end of the spring is firmly anchored to a fixed post on the surface. How far will the spring compress?
• C. A 100 g ball of putty traveling at 3.0 m/s strikes and sticks to another 100 g ball of putty at rest on a rough surface with friction. The combined balls then compress a horizontal spring with a spring constant of 3.5 N/m. The other end of the spring is firmly anchored to a fixed post on the surface. How far will the spring compress?
• D. A 100 g ball of putty is at rest next to another 100 g ball of putty on a frictionless surface. The balls are pushed together by a horizontal spring with a spring constant of 3.5 N/m. The other end of the spring is firmly anchored to a fixed post on the surface. How far will the spring compress?

Answer: (A)