Hudson county Community college STEM Division: PHY 111-02 1. In the figure, two
ID: 1780468 • Letter: H
Question
Hudson county Community college STEM Division: PHY 111-02 1. In the figure, two wooden blocks each of 0.30 kg mass are connected by a string that passes over a very light frictionless pulley. One block slides on a horizontal table, while the other hangs suspended by the string, as shown in the figure. At time O, the suspended block is 0.80 m over the floor, and the blocks are released from rest. After 2.5 s, the suspended block reaches the floor. What is the coefficient of kinetic friction between the table and the sliding block? 0.80 mExplanation / Answer
along vertical
initila velocity voy = 0
displacement y = -0.8 m
acceleration ay = -a
time t = 2.5 s
y = voy*t + (1/2)*ay*t^2
-0.8 = 0 -(1/2)*a*2.5^2
acceleration of the system a = 0.256 m/s^2
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for mass A
T - uk*mA*g = mA*a ....(1)
for mass B
mB*g - T = mB*a..........(2)
from 1 & 2
mB*g - uk*mA*g = a*(mA+mB)
0.3*9.8 - uk*0.3*9.8 = 0.256*(0.3+0.3)
coefficient of friction uk = 0.948 <<<<---ANSWER