1
JEE Main 2022 (Online) 24th June Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A boy ties a stone of mass 100 g to the end of a 2 m long string and whirls it around in a horizontal plane. The string can withstand the maximum tension of 80 N. If the maximum speed with which the stone can revolve is $${K \over \pi }$$ rev./min. The value of K is :

(Assume the string is massless and unstretchable)

A
400
B
300
C
600
D
800
2
JEE Main 2021 (Online) 27th August Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
A huge circular arc of length 4.4 ly subtends an angle '4s' at the centre of the circle. How long it would take for a body to complete 4 revolution if its speed is 8 AU per second?

Given : 1 ly = 9.46 $$\times$$ 1015 m

1 AU = 1.5 $$\times$$ 1011 m
A
4.1 $$\times$$ 108 s
B
4.5 $$\times$$ 1010 s
C
3.5 $$\times$$ 106 s
D
7.2 $$\times$$ 108 s
3
JEE Main 2021 (Online) 26th August Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
A particle of mass m is suspended from a ceiling through a string of length L. The particle moves in a horizontal circle of radius r such that $$r = {L \over {\sqrt 2 }}$$. The speed of particle will be :
A
$${\sqrt {rg} }$$
B
$${\sqrt {2rg} }$$
C
$${2\sqrt {rg} }$$
D
$${\sqrt {{{rg} \over 2}} }$$
4
JEE Main 2021 (Online) 20th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
The normal reaction 'N' for a vehicle of 800 kg mass, negotiating a turn on a 30$$^\circ$$ banked road at maximum possible speed without skidding is ____________ $$\times$$ 103 kg m/s2. [Given cos30$$^\circ$$ = 0.87, $$\mu$$s = 0.2]
A
12.4
B
7.2
C
6.96
D
10.2
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