Physics-
General
Easy
Question
Two identical small masses each of mass ‘m’ are connected by a light inextensible string on a smooth horizontal floor. A constant force F is applied at the mid point of the string as shown in the figure. The acceleration of each mass towards each other is,
- a1 =
- None of these
The correct answer is: a1 =
Let the tension in the string be T at any angular position q, the acceleration of each ball along x and y axes be ‘a’ and ‘a1’ respectively. Writing the equation of motion of m, we obtain.
S Fx = ma
ÞT Cosq = ma (1)
S Fy = ma1
ÞT Sinq = ma1 (2)
At point p, as it is accelerating with an acceleration a, therefore
F – 2 T Cosq = mpa where mp = mass of the string at the point P @ 0
ÞF = 2 T Cosq (3)
Þa1 = a tanq
where a = 
from (1).
Putting T = 
from (3), we obtain.
,Putting q = 30°
Therefore (A)
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