Two blocks are connected by a string on a pulley, set at the angle of a table. T
ID: 1441675 • Letter: T
Question
Two blocks are connected by a string on a pulley, set at the angle of a table. The block on top of the table is 3kg and the 1kg block is hanging off the side of the table. The coefficient of kinetic friction between the 3kg block (sitting on top of the desk) and the table is .15. Assuming that it starts from rest (and immediately overcomes static friction to start moving), how long does it take the block on the table to slide 30cm to the right once the anging mass is released?
The correct answer is .66s, but I need to know how to come up with this answer.
Explanation / Answer
Given
Masses (m1 =3kg and m2=1kg)
Coefficient of friction (o) = 0.15
g =9.81m/s2
distance, s = 30cm or 0.30m
Now we need to calculate time (t) =?
We know newtons laws
F= ma
F=omg
omg = ma
a = og
a = (0.15 x9.81)
acceleration (a) =1.4715 m/s2
now s = ½ a t2
0.3 = 1/2 (1.4715) t2
t2 =(0.3 x2)/1.4715
t = sqrt (0.4078)
t= 0.64sec