- #1
JJBrian
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Homework Statement
a)how much work is done by gravity as a 2kg mass is raised 2m vertically?
b)what is the change in gravitation potential energy of a 2kg mass raised 2m vertically?
c)How much work is done by a spring with a spring constant k = 50N/m as it is compressed by 0.1m from its relaxed position?
d) what is the change in the potential energy of a spring with spring constant k = 50N/m as it is compressed by0.1m from is relaxed position?
e) A 0.05kg mass is held against a spring( with spring constant k = 50N/m) while the spring is compressed by 0.1m. The mass is released and accelerated by the spring. What is the final speed of the mass?
The Attempt at a Solution
A. Wg= mgh wg = (2)(9.8)(2) = 39.2J
B. PE = mgh PE = (2)(9.8)(2) = 39.2J
C. Ws = 1/2kx^2 Ws = 1/2(50)(.1)^2 = 0.25J
D. Us = 1/2 kx^2 Us = 1/2(50)(.1)^2 = 0.25J
E. I don't know...
W = change KE
attempt 1/2kx^2 = 1/2mv^2
1/2(50)(.1)^2 = 1/2(.005)v^2
vf = sqrt(10)m/s
can someone check my work?
I need some help and explanation for problem e.
Im not too sure about the signs.