1
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
$$\tan \theta = {1 \over 4}$$
2
JEE Main 2018 (Online) 15th April Morning Slot
A uniform rod $$AB$$ is suspended from a point $$X,$$ at a variable distance $$x$$ from $$A$$, as shown, To make the rod horizontal, a mass $$m$$ is suspended from its end $$A.$$A$$set of$$(m,x)$$values is recorded. The appropriate variables that give a straight line, when plotted, are : A$$m,x$$B$$m,{1 \over x}$$C$$m,{1 \over {{x^2}}}$$D$$m,{x^2}$$3 JEE Main 2017 (Online) 9th April Morning Slot MCQ (Single Correct Answer) +4 -1 The machine as shown has 2 rods of length1 m connected by a pivot at the top. The end of one rod is connected to the floor by a stationary pivot and the end of the other rod has a roller that rolls along the floor in a slot. As the roller goes back and forth, a 2 kg weight moves up and down. If the roller is moving towards right at a constant speed, the weight moves up with a : A Constant speed B decreasing speed C increasing speed D speed which is$${3 \over 4}$$th of that of the roller when the weight is 0.4 m above the ground 4 JEE Main 2017 (Online) 9th April Morning Slot MCQ (Single Correct Answer) +4 -1 A circular hole of radius$${R \over 4}$$is made in a thin uniform disc having mass M and radius R, as shown in figure. The moment of inertia of the remaining portion of the disc about an axis passing through the point O and perpendicular to the plane of the disc is : A$${{219\,M{R^2}} \over {256}}$$B$${{237\,M{R^2}} \over {512}}$$C$${{19\,M{R^2}} \over {512}}$$D$${{197\,M{R^2}} \over {256}}