1
JEE Main 2019 (Online) 12th April Evening Slot
+4
-1
A smooth wire of length 2$$\pi$$r is bent into a circle and kept in a vertical plane. A bead can slide smoothly on the wire. When the circle is rotating with angular speed $$\omega$$ about the vertical diameter AB, as shown in figure, the bead is at rest with respect to the circular ring at position P as shown. Then the value of $$\omega$$2 is equal to -
A
$${{\sqrt 3 g} \over {2r}}$$
B
$${{2g} \over {\left( {r\sqrt 3 } \right)}}$$
C
$${{\left( {g\sqrt 3 } \right)} \over r}$$
D
$${{2g} \over r}$$
2
JEE Main 2019 (Online) 11th January Morning Slot
+4
-1
A particle is moving along a circular path with a constant speed of 10 ms–1. What is the magnitude of the change in velocity of the particle, when it moves through an angle of 60o around the centre of the circle?
A
zero
B
10 m/s
C
$$10\sqrt 2 m/s$$
D
$$10\sqrt 3 m/s$$
3
JEE Main 2019 (Online) 11th January Morning Slot
+4
-1
A body is projected at t = 0 with a velocity 10 ms–1 at an angle of 60o with the horizontal. The radius of curvature of its trajectory at t = 1s is R. neglecting air resistance and taking acceleration due to gravity g = 10 ms–2, the value of R is :
A
2.8 m
B
5.1 m
C
2.5 m
D
10.3 m
4
JEE Main 2018 (Online) 15th April Evening Slot
+4
-1
A disc rotates about its axis of symmetry in a horizontal plane at a steady rate of $$3.5$$ revolutions per second. A coin placed at a distnce of 1.25 cm from the axis of rotation remains at rest on the disc. The coefficient of friction between the coin and the disc is : (g = 10 m/s2)
A
0.5
B
0.3
C
0.7
D
0.6
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