Two objects are connected by a string of neg- ligible mass. The 7 kg block is pl
ID: 1893398 • Letter: T
Question
Two objects are connected by a string of neg-ligible mass. The 7 kg block is placed on a
smooth table top 1.5 m above the floor, and
the 4 kg block hangs over the edge of the ta-
ble. The 4 kg block is then released from rest
at a distance of 0.75 m above the floor at time
t = 0.
Explanation / Answer
Acceleration of the blocks: 4g - T = 4a ---------(i) & T = 7a ---------------(ii) =>By (i) + (ii) :- =>4 x 9.8 = 11a =>a = 3.56 m/s^2 For 7 kg block:- => By v = u + at =>v = 0 + 3.56 x 0.75 =>v = 2.67 m/s Let it take t sec to fall 1.50 m =>By s = ut + 1/2gt^2 =>1.5 = 0 + 1/2 x 9.8 x t^2 =>t = v0.306 =>t = 0.55 sec =>By R = [Ux] x t =>R = 2.67 x 0.55 =>R = 1.48 m Distance between landing points= 1.48 m