1
JEE Main 2021 (Online) 25th July Morning Shift
Numerical
+4
-1
A body of mass 2 kg moving with a speed of 4 m/s. makes an elastic collision with another body at rest and continues to move in the original direction but with one fourth of its initial peed. The speed of the two body centre of mass is $${x \over {10}}$$ m/s. Then the value of x is ___________.
2
JEE Main 2021 (Online) 22th July Evening Shift
Numerical
+4
-1
The position of the centre of mass of a uniform semi-circular wire of radius 'R' placed in x-y plane with its centre at the origin and the line joining its ends as x-axis is given by $$\left( {0,{{xR} \over \pi }} \right)$$. Then, the value of | x | is ______________.
3
JEE Main 2021 (Online) 20th July Morning Shift
Numerical
+4
-1
A rod of mass M and length L is lying on a horizontal frictionless surface. A particle of mass 'm' travelling along the surface hits at one end of the rod with a velocity 'u' in a direction perpendicular to the rod. The collision is completely elastic. After collision, particle comes to rest. The ratio of masses $$\left( {{m \over M}} \right)$$ is $${1 \over x}$$. The value of 'x' will be ____________.
4
JEE Main 2021 (Online) 18th March Evening Shift
Numerical
+4
-1
The projectile motion of a particle of mass 5 g is shown in the figure.

The initial velocity of the particle is $$5\sqrt 2$$ ms-1 and the air resistance is assumed to be negligible. The magnitude of the change in momentum between the points A and B is x $$\times$$ 10-2 kgms-1. The value of x, to the nearest integer, is __________.