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What is the difference between the centrifugal force and the centripetal force.

Important Questions on Dynamics of Uniform Circular Motion

EASY

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

A mass

m

is tied to one end of a spring and whirled in a horizontal circle with constant angular velocity. The elongation in the spring is

1 cm

. If the angular speed is doubled, the elongation in the spring is

6 cm

. The original length of the spring is

EASY

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

A body of mass

200 g

is tied to a spring of spring constant

12.5 N m^{- 1}

, while the other end of spring is fixed at point

O

. If the body moves about

O

in a circular path on a smooth horizontal surface with constant angular speed

5 rad s^{- 1}

, then the ratio of extension in the spring to its natural length will be :

MEDIUM

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

The potential energy of a particle of mass m at a distance r from a fixed point O is given by

V (r) = k r^{2} / 2

, where k is a positive constant of appropriate dimensions. This particle is moving in a circular orbit of radius R about the point O. If v is the speed of the particle and L is the magnitude of its angular momentum about O, which of the following statements is (are) true?

EASY

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

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

\frac{K}{π} rev \min^{- 1}

. The value of

K

is :
(Assume the string is massless and un-stretchable)

EASY

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

The Earth (of mass $6 \times 10^{24} kg$ ) revolves round the sun with an angular velocity of $2 \times 10^{- 7} rad s^{- 1}$ in a circular orbit of radius $1.5 \times 10^{11} km .$ The force exerted by the sun on the earth is

HARD

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

A particle of mass

m

is fixed to one end of a light spring having force constant

k

and unstretched length

l .

The other end is fixed. The system is given an angular speed

ω

about the fixed end of the spring such that it rotates in a circle in gravity free space. Then the stretch in the spring is:

MEDIUM

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

A car is moving with a constant speed of

20 m s^{- 1}

in a circular horizontal track of radius

40 m

. A bob is suspended from the roof of the car by a massless string. The angle made by the string with the vertical will be : (Take

g = 10 m s^{- 2}

)

HARD

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

The coefficient of static friction between a small block and the surface of a horizontal turntable is

0.09

. The block is placed at a distance of

0.1 m

from the centre of the turntable. At time

t = 0 s

the turntable starts rotating from rest with a constant angular acceleration of

0.5 rad \cdot s^{- 2}

. The time at which the block starts sliding is

t_{s}

. Select the correct statement(s).

EASY

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

A circular disc rotates at

60

revolutions per minute about an axis passing through its center. A coin of

18 g

is placed at a distance of

8 cm

from the center of the disc. The centrifugal force on the coin is

MEDIUM

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

A uniform rod of length

l

and density

ρ

is revolving about a vertical axis passing through its one end. If

ω

is the angular velocity of the rod then the centrifugal force per unit area of the rod is

HARD

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

A smooth wire of length

2 π 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

ω

about the vertical diameter

A B,

as shown in figure, the bead is at rest with respect to the circular ring at position

P

as shown. Then the value of

ω^{2}

is equal to:
Question Image

EASY

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

A man is supported on a frictionless horizontal surface. It is attached to a string and rotates about a fixed centre at an angular velocity

ω

. The tension in the string is

F

. If the length of string and angular velocity are doubled, the tension in string is now

MEDIUM

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

A car is moving with uniform speed over a circular bridge of radius

R

which subtends an angle of

90^{o}

at its center. Find the minimum possible speed so that the car can cross the bridge without losing contact anywhere.

HARD

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

A circular table of radius

0.5 m

has a smooth diametrical groove. A ball of mass

90 g

is placed inside the groove along with a spring of spring constant

10^{2} N {cm}^{- 1}

. One end of the spring is tied to the edge of the table and the other end to the ball. The ball is at a distance of

0.1 m

from the centre when the table is at rest. On rotating the table with a constant angular frequency of

10^{2} rad s^{- 1}

, the ball moves away from the centre by a distance nearly equal to

HARD

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

Two cars $A$ and $B$ start racing at the same time on a flat race track which consists of two straight sections each of length $100 π$ and one circular section as shown in the figure. The rule of the race is that each car must travel at constant speed at all times without even skidding.

Question Image

EASY

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

A stone of mass 0.3 kg attached to a 1.5 m long string is whirled around in a horizontal circle at a speed of 6 m/s. The tension in the string is

HARD

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

A car is moving in a circular horizontal track of radius

10 m

with a constant speed of

10 m/s

. A plumb bob is suspended from the roof of the car by a light rigid rod of length

1 m

. the angle made by the rod with the track is

MEDIUM

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

A particle moves in a circular orbit under the action of a central attractive force inversely proportional to the distance

r

. The speed of the particle is,

EASY

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

A particle of mass

m

is moving in a horizontal circle of radius

r

under a centripetal force equal to

- \frac{k}{r^{2}}

. The total kinetic energy of the particle is,

EASY

Physics>Mechanics>Dynamics of Uniform Circular Motion>Centrifugal Force

A ball of mass 0.25 kg attached to the end of a string of length 1.96 m is moving in a horizontal circle. The string will break if the tension is more than 25 N. What is the maximum speed with which ball can be moved?

What is the difference between the centrifugal force and the centripetal force.

Important Questions on Dynamics of Uniform Circular Motion

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