- #1
Angela_vaal
- 59
- 1
Homework Statement
A 1.40 kg block slides with a speed of 0.885 m/s on a frictionless horizontal surface until it encounters a spring with a force constant of 637 N/m . The block comes to rest after compressing the spring 4.15 cm.
Part A
Find the spring potential energy, U, the kinetic energy of the block, K, and the total mechanical energy of the system, E, for compressions of 0 cm.
Part B
Find the spring potential energy, U, the kinetic energy of the block, K, and the total mechanical energy of the system, E, for compressions of 1.00 cm.
Part C
Find the spring potential energy, U, the kinetic energy of the block, K, and the total mechanical energy of the system, E, for compressions of 2.00 cm.
Part D
Find the spring potential energy, U, the kinetic energy of the block, K, and the total mechanical energy of the system, E, for compressions of 3.00 cm.
Part E
Find the spring potential energy, U, the kinetic energy of the block, K, and the total mechanical energy of the system, E, for compressions of 4.00 cm.
Homework Equations
Potential energy= 1/2Kx2
Kinetic energy=1/2mv2
Mechanical energy=KE+PE
The Attempt at a Solution
I got the first answer correct using these equations. However, when I use these equations for part B I get them wrong. For example, this is what I did.
part B) PE=(.5)(.01m)(.0415m)2 =8.6x10-6J
KE= (.5)(1.40kg)(.885m/s)2 = .548 J
ME= .548J+8.6x10-6 = .548 J
I don't know what I am doing wrong if someone can please explain I would appreciate it! Also, I have seen in other examples that the KE is supposed to change with each compression. How? if the mass and the velocity remain the same?