1
JEE Main 2021 (Online) 26th February Evening Shift
+4
-1
The trajectory of a projectile in a vertical plane is y = $$\alpha$$x $$-$$ $$\beta$$x2, where $$\alpha$$ and $$\beta$$ are constants and x & y are respectively the horizontal and vertical distances of the projectile from the point of projection. The angle of projection $$\theta$$ and the maximum height attained H are respectively given by :
A
$${\tan ^{ - 1}}\alpha ,{{{\alpha ^2}} \over {4\beta }}$$
B
$${\tan ^{ - 1}}\alpha ,{{4{\alpha ^2}} \over \beta }$$
C
$${\tan ^{ - 1}}\left( {{\beta \over \alpha }} \right),{{{\alpha ^2}} \over \beta }$$
D
$${\tan ^{ - 1}}\beta ,{{{\alpha ^2}} \over {2\beta }}$$
2
JEE Main 2021 (Online) 25th February Evening Shift
+4
-1
A stone is dropped from the top of a building. When it crosses a point 5 m below the top, another stone starts to fall from a point 25 m below the top. Both stones reach the bottom of building simultaneously. The height of the building is :
A
50 m
B
25 m
C
45 m
D
35 m
3
JEE Main 2021 (Online) 25th February Morning Shift
+4
-1
An engine of a train, moving with uniform acceleration, passes the signal-post with velocity u and the last compartment with velocity v. The velocity with which middle point of the train passes the signal post is :
A
$${{u + v} \over 2}$$
B
$$\sqrt {{{{v^2} - {u^2}} \over 2}}$$
C
$${{v - u} \over 2}$$
D
$$\sqrt {{{{v^2} + {u^2}} \over 2}}$$
4
JEE Main 2021 (Online) 24th February Morning Shift
+4
-1
If the velocity-time graph has the shape AMB, what would be the shape of the corresponding acceleration-time graph?

A
B
C
D
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