1
JEE Main 2022 (Online) 24th June Morning Shift
+4
-1

A projectile is projected with velocity of 25 m/s at an angle $$\theta$$ with the horizontal. After t seconds its inclination with horizontal becomes zero. If R represents horizontal range of the projectile, the value of $$\theta$$ will be :

[use g = 10 m/s2]

A
$${1 \over 2}{\sin ^{ - 1}}\left( {{{5{t^2}} \over {4R}}} \right)$$
B
$${1 \over 2}{\sin ^{ - 1}}\left( {{{4R} \over {5{t^2}}}} \right)$$
C
$${\tan ^{ - 1}}\left( {{{4{t^2}} \over {5R}}} \right)$$
D
$${\cot ^{ - 1}}\left( {{R \over {20{t^2}}}} \right)$$
2
JEE Main 2021 (Online) 1st September Evening Shift
+4
-1
The ranges and heights for two projectiles projected with the same initial velocity at angles 42$$^\circ$$ and 48$$^\circ$$ with the horizontal are R1, R2 and H1, H2 respectively. Choose the correct option :
A
R1 > R2 and H1 = H2
B
R1 = R2 and H1 < H2
C
R1 < R2 and H1 < H2
D
R1 = R2 and H1 = H2
3
JEE Main 2021 (Online) 31st August Morning Shift
+4
-1
A helicopter is flying horizontally with a speed 'v' at an altitude 'h' has to drop a food packet for a man on the ground. What is the distance of helicopter from the man when the food packet is dropped?
A
$$\sqrt {{{2gh{v^2} + 1} \over {{h^2}}}}$$
B
$$\sqrt {2gh{v^2} + {h^2}}$$
C
$$\sqrt {{{2{v^2}h} \over g} + {h^2}}$$
D
$$\sqrt {{{2gh} \over {{v^2}}} + {h^2}}$$
4
JEE Main 2021 (Online) 27th August Evening Shift
+4
-1
Water drops are falling from a nozzle of a shower onto the floor, from a height of 9.8 m. The drops fall at a regular interval of time. When the first drop strikes the floor, at that instant, the third drop begins to fall. Locate the position of second drop from the floor when the first drop strikes the floor.
A
4.18 m
B
2.94 m
C
2.45 m
D
7.35 m
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