1
JEE Main 2019 (Online) 9th January Morning Slot
+4
-1
Two masses m and $${m \over 2}$$ are connected at the two ends of a massless rigid rod of length l. The rod is suspended by a thin wire of torsional constant k, at the centre of mass of the rod-mass system(see figure). Because of torsional constant k, the restoring torque is $$\tau$$ = k$$\theta$$ for angular displacement $$\theta$$. If the rod is rotated by $$\theta$$0 and released, the tension in it when it passes through its mean position will be :

A
$${{3k{\theta _0}^2} \over l}$$
B
$${{2k{\theta _0}^2} \over l}$$
C
$${{k{\theta _0}^2} \over l}$$
D
$${{k{\theta _0}^2} \over {2l}}$$
2
JEE Main 2018 (Online) 15th April Morning Slot
+4
-1
A force of $$40$$ $$N$$ acts on a point $$B$$ at the end of an $$L$$-shaped object, as shown in the figure. The angle $$\theta$$ that will produce maximum moment of the force about point $$A$$ is given by :

A
$$\tan \theta = {1 \over 2}$$
B
$$\tan \theta = 2$$
C
$$\tan \theta = 4$$
D
$$\tan \theta = {1 \over 4}$$
3
JEE Main 2015 (Offline)
+4
-1
A particle of mass $$m$$ moving in the $$x$$ direction with speed $$2v$$ is hit by another particle of mass $$2m$$ moving in the $$y$$ direction with speed $$v.$$ If the collision is perfectly inelastic, the percentage loss in the energy during the collision is close to:
A
$$56\%$$
B
$$62\%$$
C
$$44\%$$
D
$$50\%$$
4
JEE Main 2013 (Offline)
+4
-1
This question has statement $${\rm I}$$ and statement $${\rm I}$$$${\rm I}$$. Of the four choices given after the statements, choose the one that best describes the two statements.

Statement - $${\rm I}$$: A point particle of mass $$m$$ moving with speed $$\upsilon$$ collides with stationary point particle of mass $$M.$$ If the maximum energy loss possible is given as $$f\left( {{1 \over 2}m{v^2}} \right)$$, then $$f = \left( {{m \over {M + m}}} \right).$$

Statement - $${\rm II}$$: Maximum energy loss occurs when the particles get stuck together as a result of the collision.

A
Statement - $${\rm I}$$ is true, Statement - $${\rm II}$$ is true; Statement - $${\rm II}$$ is the correct explanation of Statement - $${\rm I}$$.
B
Statement - $${\rm I}$$ is true, Statement - $${\rm II}$$ is true; Statement - $${\rm II}$$ is not the correct explanation of Statement - $${\rm I}$$.
C
Statement - $${\rm I}$$ is true, Statement - $${\rm II}$$ is false
D
Statement - $${\rm I}$$ is false, Statement - $${\rm II}$$ true.
JEE Main Subjects
Physics
Mechanics
Electricity
Optics
Modern Physics
Chemistry
Physical Chemistry
Inorganic Chemistry
Organic Chemistry
Mathematics
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