1@gsns u r wrong
and @rohan 2007 u r rite
A block of mass 1kg and density 0.8g/cm3 is held stationary with the help of a string as shown in the figure. the tank is accelerating upwards with an acceleration a=1.0m/s2
find:
the tension in the string
if the string is now cut the acceleration of the block
(take g=10m.s2, density of water = 103kg/m3
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UP 0 DOWN 0 0 6
6 Answers
1applying equation of motion
B-mg-T=ma
where a= accelaration of block
B=buoyant force
further buoyant force=ÏaV + ÏgV
V= volume of object which can be obtained as V=m/Ïobject
we get T
further by cuting the thread the buoyant force is unchanged except that T vanishes
so now anew will be
manew=B-mg
1I'm working with symbols here.
Let mass=m ; density of block= p ; density of water= d;
accln. due to gravity= g; Tension=T ; accln. of tank=a.
Since the block is in equilibrium in the reference frame attached to the tank,
T + m(g+a) = (m/p)d(g+a)
So, T= (m/p)d(g+a) - m(g+a)
When string is cut, net force on the block= T upward.
So accln.=A= (T/m) = (d/p)(g+a)-g upward, with respect to the reference frame attached to the tank.
With respect to the ground reference frame,
accln.= A+a.
Am I correct???