Free Printable XI DPP-39 ROTATION MOTION (Rotational Kinetics)

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XI DPP-39 ROTATION MOTION (Rotational Kinetics)

Total questions: 21

Worksheet time: 1hrs 3mins

Name

Class

Date

A circular ring of wire of mass M and radius R is making n revolutions/sec about an axis passing through a point on its rim and perpendicular to its plane. The kinetic energy of rotation of the ring is given by-

4π²MR²n²

2π²MR²n²

1/2 π²MR²n²

8 π²MR²n²

Rotational kinetic energy of a disc of constant moment of inertia is -

directly proportional to angular velocity

inversely proportional to angular velocity

inversely proportional to square of angular velocity

directly proportional to square of angular velocity

The kinetic energy of a body rotating with constant angular velocity only depends upon its -

mass

radius of gyration

moment of inertia

angular momentum

Rotational kinetic energy of a given body about an axis is proportional to -

time period

(time period)²

(time period)^-1

(time period)^–2

A circular disc has a mass of 1kg and radius 40 cm. It is rotating about an axis passing through its centre and perpendicular to its plane with a speed of 10rev/s. The work done in joules in stopping it would be-

47.5

158

A fly wheel of moment of inertia I is rotating at n revolutions per sec. The work needed to double the frequency would be -

2π²In²

4π²In²

6π²In²

8π²In²

A thin bar of length L is suspended from one end and rotated at a speed of n revolutions per second. The rotational kinetic energy of the bar is -

2ML²π²n²

1/2 ML²π²n²

2/3 ML²π²n²

1/6 ML²π²n²

A ring of mass 1kg and diameter 1m is rolling on a plane road with a speed 2m/s. Its kinetic energy would be -

1 joule

4 joule

2 joule

0.5 joule

A disc is rolling without slipping. The ratio of its rotational kinetic energy and translational kinetic energy would be -

1 : 1

2 : 1

1 : 2

1 : 4

10.

A disc rolls on a table. The ratio of its K.E. of rotation to the total K.E. is -

2/5

1/3

5/6

2/3

11.

A hoop having a mass of 1kg and a diameter of 1 meter rolls along a level road at 2m/sec. Its total K.E. would be -

1 Joule

4 joules

2 joules

0.5 joule

12.

A cylinder of mass M and radius R rolls on an inclined plane. The gain in kinetic energy is

1/2 MV²

\frac{1}{2}I^{\omega2}

$\frac{3}{4}Mv^2$

$\frac{3}{4}I^{\omega2}$

13.

A disk and a ring of the same mass are

rolling to have the same kinetic energy. What is ratio of their velocities of centre of mass

(4:3)^1/2

(3 : 4)^1/2

(2)^1/2 : (3) ^1/2

(3)^1/2 : (2)^1/2

14.

A rolling body has the maximum fraction of rotational energy equal to -

1/2

1/3

2/3

2/7

15.

A solid cylinder starts rolling from a height h on an inclined plane. At some instant t, the ratio of its rotational K.E. and the total K.E. would be

1 : 2

1 : 3

2 : 3

1 : 1

16.

When different regular bodies roll down along an inclined plane from rest, then acceleration will be maximum for a body whose -

radius of gyration is least

mass is least

surface area is maximum

moment of inertia is maximum

17.

A sphere rolls down an inclined plane through a height h. Its velocity at the bottom would be

\sqrt{2gh}

$\sqrt{\frac{7}{10}gh}$

$\sqrt{\frac{10}{7}gh}$

$\left(\sqrt{\frac{10}{7}}\right)gh$

18.

If the applied torque is directly proportional to the angular displacement θ, then the work done in rotating the body through an angle θ would be - (C is constant of proportionality)

Cθ

1/2 Cθ

1/2 Cθ²

Cθ²

19.

Rotational power in rotational motion is -

$\overrightarrow{\omega}.\overrightarrow{\tau}$

$\overrightarrow{\omega}\times\overrightarrow{\tau}$

$\overrightarrow{\tau}.\overrightarrow{\alpha}$

$\overrightarrow{\tau}.\times\overrightarrow{\alpha}$

20.

A small ball of radius r rolls down without sliding in a big hemispherical bowl. of radius R. What would be the ratio of the translational and rotational kinetic energies at the bottom of the bowl

2 : 1

3 : 2

4 : 3

5 : 2

21.

A wheel whose radius is R and moment of inertia about its-own axis is I, rotates freely about its own axis. A rope is wrapped on the wheel. A body of mass m is suspended from the free end of the rope. The body is released from rest. The velocity of the body after falling a distance h would be -

\left(\frac{mgh}{I}\right)\ ^{1/2}

$\left(\frac{2mgh}{m+I}\right)\ ^{1/2}$

$\left(\frac{2mgh}{m+I/r^2}\right)\ ^{1/2}$

$\left(\frac{m+I}{2mgh}\right)\ ^{1/2}$

100 %

XI DPP-39 ROTATION MOTION (Rotational Kinetics)

Total questions: 21

Worksheet time: 1hrs 3mins

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