A science teacher pushes a 0.75 kg cube against an ideal spring with a spring constant of 300 N/m. The spring is compressed to a distance of 5.0 cm. The teacher releases the cube. After moving over the smooth horizontal part of the setup shown in the figure below, the cube slides down over a rough ramp, making an angle of 15° with the horizontal. The coefficient of kinetic friction between the cube and ramp is 0.25. Determine the speed of the cube just after leaving contact with the spring.

• A. 1.0 m/s
• B. 1.2 m/s
• C. 4.5 m/s
• D. 20 m/s

Answer: (A)