Note: This question is worth 2 points. A spring with spring constant k has a mas

Question

Note: This question is worth 2 points.
A spring with spring constant k has a mass on one end, with the other end attached to the wall. The mass is initially at rest on a horizontal frictionless surface at a location we will call x = 0. Your partner grabs the mass and pulls it out to x = L. She then lets the mass go, causing the system to oscillate. Which of the following are true? More than one answer may be correct. Use the normal assumptions when working this problem.

1.The total energy is at a maximum for some location x = D between x = L and x = -L (but not x = 0).

2.The total energy is constant regardless of the location of the mass.

3.When the mass is at x = L (or -L), its kinetic energy is zero.

4.The total energy is at a maximum when the mass is at x = L, but not at -L.

5.When the mass is at x = L (or -L), its kinetic energy is at its maximum.

6.When the mass is at x = 0, the elastic potential energy is zero.

7.The total energy is larger than at any other point when the mass is at x = 0.

8.When the mass is at x = 0, the elastic potential energy is at a maximum.

Explanation / Answer

1.The total energy is at a maximum for some location x = D between x = L and x = -L (but not x = 0).

FALSE

REASON: Since floor is frictionless so the total energy will remain conserved, it will be same for all positions

2.The total energy is constant regardless of the location of the mass.

TRUE

REASON: We discussed in above

total energy is always E = 0.5 KA2

3.When the mass is at x = L (or -L), its kinetic energy is zero.

TRUE

REASON: Since kinetic energy is given by KE = 0.5 K(A2 - x2)

here if we plug in x = A (or -A) the KE becomes ZERO

4.The total energy is at a maximum when the mass is at x = L, but not at -L.

FALSE

REASON: As we discussed above that total energy is always constant.

5.When the mass is at x = L (or -L), its kinetic energy is at its maximum.

FALSE

REASON: As we have discussed in #3 that Kinetic Energy is ZERO at x = +A (or -A) so it can not be maximum but it is minimum

6.When the mass is at x = 0, the elastic potential energy is zero.

TRUE

REASON: Elastic potential energy is given by U= 0.5 Kx2

at x = 0, U = 0

7.The total energy is larger than at any other point when the mass is at x = 0.

FALSE

REASON: As we discussed in above parts total energy always remains constant.

8.When the mass is at x = 0, the elastic potential energy is at a maximum.

FALSE

REASON: As we discussed above that at x = 0 potential energy is ZERO it is not maximum

Related Questions

Navigate

• Browse (All)
• Browse N
• Subjects

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