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NEET - Physics Circular Motion Practice Q & A Page: 2
23297.When the angular velocity of a uniformly rotating body has increased thrice the resultant of forces applied to it increases by 60 N. find the acceleration of the body in two cases if the mass of the body is 3 kg
2.5 m s–2, 7.5 m s–2
7.5 m s–2, 67.5 m s–2
5 m s–2, 45 m s–2
2.5 m s–2, 22.5 m s–2
23298.A car sometimes overturns while taking a turn. When it overturns, it is
the inner wheel which leaves the ground first
the outer wheel which leaves the ground first
both the wheel leave the ground simultaneously
either inner wheel or the outer wheel leaves the ground
23299.A particle of mass ‘m’ moves with a constant speed along a circular path of radius r under the action of a force F. Its speed is given by
$\sqrt{\dfrac{Fr}{m}}$
$\sqrt{\dfrac{F}{mr}}$
$\sqrt{\dfrac{F}{r}}$
$\sqrt{Fmr}$
23300.A coin kept on a rotating gramophone disc just begins to slip if its centre is at a distance of 8 cm from the centre of the disc. The angular velocity of the gramophone disc is then doubled. Through what distance, the coin should be shifted towards the centre, so that the coin will just slip?
2 cm
4 cm
6 cm
16 cm
23301.If a cycle wheel of radius 0.4 m completes one revolution in one second, then acceleration of the cycle is
0.4 $π$ m/s2
0.8 $π$ m/s2
0.4 $π$2 m/s2
1.6 $π$2 m/s2
23302.A cyclist goes round a circular path of circumference 343 m in $\sqrt{22}$s. The angle made by him, with the vertical is
42°
43°
44°
45°
23303.Kinetic energy of a particle moving along the circle is $ax^2$. If R is the radius of the circle. The radial force on the particle is
$\dfrac{2ax^2}{R}$
$\left[\dfrac{1 + x^2}{R^2}\right]^{1/2}$
$2ax$
$\dfrac{2aR^2}{x}$
23304.The angular speed of a flywheel making 180 r.p.m. is
2$π$ rad/s
4$π$ rad/s
6$π$ rad/s
3$π$2 rad/s
23305.The angular velocity of a wheel is 70 rad/sec. If the radius of the wheel is 0.5 m, then linear velocity of the wheel is
10 m/s
20 m/s
35 m/s
70 m/s
23306.A car has a linear velocity v on a circular track of radius r. If its speed is increasing at a rate of a m/s2, then its resultant acceleration will be
$\sqrt{\left(\dfrac{v^2}{r}\right)^2 + a^2}$
$\sqrt{\left(\dfrac{v^2}{r}\right)^2 – a^2}$
$\left(\dfrac{v^2}{r}\right)^2 + a^2$
$\left(\dfrac{v^2}{r}\right)^2 – a^2$
23307.A cyclist turns around a curve at 15 miles per hour. If he turns at double the speed, the tendency of overturn is
doubled
quadrupled
halved
unchanged
23308.The maximum safe speed of a vehicle on a circular tract is 15 km/hr. When the track becomes wet, the maximum safe speed is 10 km/hr. The ratio of coefficient of friction of the dry track to that of Wet track is
9 : 4
3 : 2
2 : 3
1.5 : 1
23309.A fighter aeroplane flying in the sky dives with a speed of 360 km/hr in a vertical circle of radius 200 m. Weight of the pilot sitting in it is 75 kg. What will be the value of force with which the pilot presses his seat when the aeroplane is at highest position (g = 10 m/s2)
3000 N
1500 N
(75 × g)N
300 N
23310.A frictional track ABCDE ends in a circular loop of radius R, body slides down the track from point A which is at a height h of 5 cm. Maximum value of R for the body to successfully complete the loop is:
5 cm
$\dfrac{15}{4}$ cm
$\dfrac{10}{3}$ cm
2 cm
23311.A man whirls a stone of mass 250 gram, tied at the end of a string of length 2 m in a horizontal circle and at a height of 5 m from the ground. The string breaks and the stone flies off tangenitially and strikes the ground at a horizontal distance of 10 m from the man. What was the magnitude of the centripetal acceleration of the stone, when it was moving in the circle? (g = 10 m/s2)
50 m/s2
40 m/s2
30 m/s2
25 m/s2
23312.A mass suspended on a frictional less horizontal surface. It is attached to a string and rotates about a fixed centre at an angular velocity ω0. If length of the string and angular velocity are doubled the tension in the string which was initially T0 is now
T0
$\dfrac{T_0}{2}$
4 T0
8 T0
23313.What is the apparent weight of a body of mass m attached at the end of a string and which is just completing the loop in a vertical circle, at the lowest point in its path?
0
mg
3 mg
6 mg
23314.A metal sphere of mass 0.1 kg is attached to an inextensible string of length 130 cm whose upper end is fixed to the rigid support. If the sphere is made to describe a horizontal circle of radius 50 cm, the time for its one revolution is near about
1.2 sec
2.2 sec
1.5 sec
3 sec
23315.A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle. The motion takes place in a plane. It follows that
its velocity is constant
its acceleration is constant
its motion is linear
its motion is circular
23316.A particle is moving along a circular path. Let $v$, ω, α and ac be its linear velocity, angular velocity, angular acceleration and centripetal acceleration respectively. Which is the wrong statement from the following?
$\overrightarrow{\omega} \perp \overrightarrow{v}$
$\overrightarrow{\omega} \perp \overrightarrow{a}_c$
$\overrightarrow{\omega} \perp \overrightarrow{\alpha}$
$\overrightarrow{v} \perp \overrightarrow{a}_c$
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