NTA JEE Main 20th July 2021 Shift 2

Two vectors $$\vec{P}$$ and $$\vec{Q}$$ have equal magnitudes. If the magnitude of $$\vec{P} + \vec{Q}$$ is $$n$$ times the magnitude of $$\vec{P} - \vec{Q}$$, then angle between $$\vec{P}$$ and $$\vec{Q}$$ is:

If time $$(t)$$, velocity $$(v)$$, and angular momentum $$(l)$$ are taken as the fundamental units. Then the dimension of mass $$(m)$$ in terms of $$t$$, $$v$$ and $$l$$ is:

A body at rest is moved along a horizontal straight line by a machine delivering a constant power. The distance moved by the body in time $$t$$ is proportional to:

A boy reaches the airport and finds that the escalator is not working. He walks up the stationary escalator in time $$t_1$$. If he remains stationary on a moving escalator then the escalator takes him up in time $$t_2$$. The time taken by him to walk up on the moving escalator will be:

If the kinetic energy of a moving body becomes four times its initial kinetic energy, then the percentage change in its momentum will be:

A body rolls down an inclined plane without slipping. The kinetic energy of rotation is 50% of its translational kinetic energy. The body is:

A satellite is launched into a circular orbit of radius $$R$$ around earth, while a second satellite is launched into a circular orbit of radius 1.02 $$R$$. The percentage difference in the time periods of the two satellites is:

Consider a binary star system of star A and star B with masses $$m_A$$ and $$m_B$$ revolving in a circular orbit of radii $$r_A$$ and $$r_B$$, respectively. If $$T_A$$ and $$T_B$$ are the time period of star A and star B, respectively, then:

The length of a metal wire is $$\ell_1$$, when the tension in it is $$T_1$$ and is $$\ell_2$$ when the tension is $$T_2$$. The natural length of the wire is:

Two small drops of mercury each of radius $$R$$ coalesce to form a single large drop. The ratio of total surface energy before and after the change is: