PHYSICS 1403, QUIZ 4
Chapter 6, October 26, 2004
Partial credit will be LIBERAL, provided that you show your work!
USE BACK IF NEEDED! (Please tell me if you’ve done so!)
Name: ______________________
1.
(10 points) Answer in complete, grammatically correct, English sentences! You may supplement the
sentences with equations if you explain what each symbol in the equations means!
a. State the Work-Energy Principle.
b.
2.
State the Principle of Conservation of Mechanical Energy.
(20 points) See figure. Use energy methods to solve this!!! NO credit will be given for force methods!
You don’t need force components or the incline angle θ to solve this! A block, mass m = 4 kg, is on
a horizontal, frictionless surface. It is pressed against an ideal
spring, of constant k = 700 N/m. It is initially at rest, as on the right
of the figure at point A. At point A, the spring is compressed a
distance x = 0.25 m from its equilibrium position. The block is
released and it moves to point B, which is at the bottom of a
frictionless incline. It then moves up the incline and stops at point
C at the right of the figure, a at height h above the original position.
a. Compute the elastic (spring) potential energy of the block at point A.
b. Compute the kinetic energy and speed of the block at point B. What Physical Principle did you
use?
c. Compute gravitational potential energy of the block at point C and the height
h at which it stops. What Physical Principle did you use?
d. Compute the velocity of the block when it is at height y = 0.3 m above the
horizontal surface (above point B and below point C).