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1
JEE Main 2021 (Online) 17th March Morning Shift
+4
-1
A car accelerates from rest at a constant rate $$\alpha$$ for some time after which it decelerates at a constant rate $$\beta$$ to come to rest. If the total time elapsed is t seconds, the total distance travelled is :
A
$${{4\alpha \beta } \over {(\alpha + \beta )}}{t^2}$$
B
$${{2\alpha \beta } \over {(\alpha + \beta )}}{t^2}$$
C
$${{\alpha \beta } \over {2(\alpha + \beta )}}{t^2}$$
D
$${{\alpha \beta } \over {4(\alpha + \beta )}}{t^2}$$
2
JEE Main 2021 (Online) 16th March Evening Shift
+4
-1
A mosquito is moving with a velocity $$\overrightarrow v = 0.5{t^2}\widehat i + 3t\widehat j + 9\widehat k$$ m/s and accelerating in uniform conditions. What will be the direction of mosquito after 2 s?
A
$${\tan ^{ - 1}}\left( {{\sqrt {85} } \over 6}\right)$$ from y-axis
B
$${\tan ^{ - 1}}\left( {{5 \over 2}} \right)$$ from y-axis
C
$${\tan ^{ - 1}}\left( {{2 \over 3}} \right)$$ from x-axis
D
$${\tan ^{ - 1}}\left( {{5 \over 2}} \right)$$ from x-axis
3
JEE Main 2021 (Online) 16th March Morning Shift
+4
-1
The velocity-displacement graph describing the motion of bicycle is shown in the figure.

The acceleration-displacement graph of the bicycle's motion is best described by :
A
B
C
D
4
JEE Main 2021 (Online) 26th February Evening Shift
A scooter accelerates from rest for time t1 at constant rate a1 and then retards at constant rate a2 for time t2 and comes to rest. The correct value of $${{{t_1}} \over {{t_2}}}$$ wil be :
$${{{a_1} + {a_2}} \over {{a_2}}}$$
$${{{a_1} + {a_2}} \over {{a_1}}}$$
$${{{a_2}} \over {{a_1}}}$$
$${{{a_1}} \over {{a_2}}}$$