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1
JEE Main 2021 (Online) 17th March Morning Shift
MCQ (Single Correct Answer)
+4
-1
A modern grand - prix racing car of mass m is travelling on a flat track in a circular arc of radius R with a speed v. If the coefficient of static friction between the tyres and the track is $$\mu$$s, then the magnitude of negative lift FL acting downwards on the car is : (Assume forces on the four tyres are identical and g = acceleration due to gravity)

JEE Main 2021 (Online) 17th March Morning Shift Physics - Circular Motion Question 14 English
A
$$m\left( {g - {{{v^2}} \over {{\mu _s}R}}} \right)$$
B
$$ - m\left( {g + {{{v^2}} \over {{\mu _s}R}}} \right)$$
C
$$m\left( {{{{v^2}} \over {{\mu _s}R}} - g} \right)$$
D
$$m\left( {{{{v^2}} \over {{\mu _s}R}} + g} \right)$$
2
JEE Main 2021 (Online) 16th March Evening Shift
MCQ (Single Correct Answer)
+4
-1
Statement I : A cyclist is moving on an unbanked road with a speed of 7 kmh$$-$$1 and takes a sharp circular turn along a path of radius of 2m without reducing the speed. The static friction coefficient is 0.2. The cyclist will not slip and pass the curve. (g = 9.8 m/s2)

Statement II : If the road is banked at an angle of 45$$^\circ$$, cyclist can cross the curve of 2m radius with the speed of 18.5 kmh$$-$$1 without slipping.

In the light of the above statements, choose the correct answer from the options given below.
A
Statement I is incorrect and statement II is correct
B
Both statement I and statement II are true
C
Statement I is correct and statement II is incorrect
D
Both statement I and statement II are false
3
JEE Main 2019 (Online) 11th January Morning Slot
MCQ (Single Correct Answer)
+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
MCQ (Single Correct Answer)
+4
-1
Change Language
English
Hindi
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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