Hi, My teacher assigned me this exercise in order to pass the course but I could

Question

Hi,

My teacher assigned me this exercise in order to pass the course but I could not solve it properly (please help me). I solved it using linear momentum in here http://snag.gy/ookHd.jpg and it's ok, however he is asking for another way to solve it (different from linear momentum itself) using another approach in which each ball is treated separately. He said the answer is not easy and it could be used any other topic of physics (impulse, equilibrium, elasticity, etc). Could you please help me. Thanks in advance

Two masses of 1.5-kg and 2-kg respectively are pressed against opposite ends of a light spring of force constant 1.75N/cm, compressing the spring by 20.0 cm from its normal length. Find the speed of each mass when it has moved free of the spring on a frictionless horizontal table

Explanation / Answer

Now by law of conservation of energy

1/2 m1v1f^2+1/2m2v2f^2 =1/2m1v1i^2+1/2m2v2i^2

1/2 m1v1f^2+1/2m2v2f^2 = 1/2kx^2

m1v1f^2+m2v2f^2 = kx^2

1.5v1f^2 + 2.0(0.75v1f^2) =1/2*1.75*0.2^2     => v1f = 0.11m/s

Plugging this value in (1) we get v2f = 0.75*0.11 = - 0.0825 m/s

Note that both masses have opposite final velocities

Related Questions

Navigate

• Browse (All)
• Browse H
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.