A block of mass 5 kg is placed against a horizontal spring that is compressed. T
ID: 1486452 • Letter: A
Question
A block of mass 5 kg is placed against a horizontal spring that is compressed. The spring is released and the block moves along a horizontal surface, leaving the spring behind. The coefficient of kinetic friction between the block and the sufrace is .3. After the block has traveled 3 m from its initial position, its speed is 6.00 m/s.
a) What is the magnitude of the friction force on the box while it is moving? 14.7 N
b) During the 3.00 m displacement of the block, how much work does the friction force do on the block? -44.1 J
c) How much elastic potential energy was initially stored in the spring, if the spring gives up all its stored energy? 134.1 J
I am having trouble working this problem out. Thank you in advance!
Explanation / Answer
Apply the formula for frictional force,
the magnitude of the friction force on the box while it is moving Ff = umg
Ff = 0.3 * 5 * 9.8
Ff = 14.7 N
--------------------------
Work Done work does the friction force do on the block W = -Fs d
here d is distance
W = -14.7 * 3
W = -44.1 Joules
------------------------------------------------------------
elastic potential energy was initially stored in the spring U = Wfs + KE
= 44.1 + 0.5 * mv^2
= 44.1 + 0.5 * 5* 6^2
= 134.1 Joules
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.