Chapter 4: Rotational Motion & Gravitation (Set-1)

Torque is defined as:

A r×p
B r×F
C F×t
D p×v

SI unit of torque is:

A N
B J
C N·m
D J/s

Angular momentum of a particle is given by:

A
B rF
C r×p
D mv²

Angular momentum is conserved when:

A No external force acts
B No external torque acts
C No internal force acts
D Velocity is constant

If torque is zero, angular momentum:

A Increases
B Decreases
C Remains constant
D Becomes zero

Direction of torque is given by:

A Right-hand rule
B Left-hand rule
C Newton’s rule
D Rutherford’s rule

A door is easiest to open when force is applied:

A Near hinges
B At midpoint
C At the edge
D Vertically downward

Torque becomes zero when:

A Force increases
B Angle is 90°
C Displacement is zero
D Force is along the line of pivot

Rotational analogue of force is:

A Momentum
B Work
C Torque
D Angular momentum

Angular impulse equals change in:

A Linear momentum
B Angular momentum
C Torque
D Angular velocity only

Moment of inertia depends on:

A Force only
B Mass distribution
C Speed
D Time

SI unit of moment of inertia is:

A kg
B kg·m
C kg·m²
D N·m

Which has greatest moment of inertia about central axis?

A Solid sphere
B Solid cylinder
C Hollow sphere
D Ring

Moment of inertia of a rod about its centre is proportional to:

A L
B
C
D 1/L

Doubling the distance of mass from axis increases MoI by:

A
B
C
D 16×

Rotational inertia is greatest when:

A Mass is close to axis
B Mass is far from axis
C Body is rotating slowly
D Body is weightless

Parallel axis theorem adds:

A ML
B ML²
C MH
D Md²

The rotational kinetic energy is:

A ½ m v²
B ½ I ω²
C
D

Moment of inertia of point mass is:

A mr
B mr²
C
D m/r

Least moment of inertia is for:

A Ring
B Hollow sphere
C Solid cylinder
D Solid sphere

Rotational analogue of Newton’s second law:

A F = ma
B τ = Iα
C a = F/m
D p = mv

Angular acceleration is produced by:

A Linear force
B Centripetal force
C Torque
D Mass

Rolling without slipping means:

A v = rω
B v = ω/r
C v = r/ω
D v = r²ω

If torque increases, angular acceleration:

A Increases
B Decreases
C Remains constant
D Becomes zero

Work done in rotational motion =

A τα
B τω
C τθ
D

Power in rotational motion is:

A Fv
B τω
C
D dI/dt

In pure rolling, friction:

A Does work
B Does no work
C Always increases KE
D Is zero

Angular velocity is measured in:

A rad/s
B rad
C m/s²
D m/s

A body with larger MoI will:

A Rotate faster
B Resist rotational change more
C Fall freely
D Have more KE

Rotational equilibrium occurs when:

A Net torque = 0
B Net force = 0
C Angular momentum = 0
D MoI = 0

A central force:

A Depends on time
B Acts along line joining two bodies
C Acts perpendicular to radius
D Is always repulsive

Central forces always conserve:

A Linear momentum
B Torque
C Angular momentum
D Force

Non-central force causes:

A No torque
B Change in angular momentum
C No work
D No rotation

Gravitational force is a:

A Central force
B Non-central force
C Tangential force
D Perpendicular force

Central forces result in motion:

A Circular
B Parabolic
C Planar
D Random

Non-central forces change:

A Radius only
B Plane of motion
C Angular momentum
D Potential energy only

Gravitational force follows:

A Linear law
B Inverse law
C Square law
D Inverse square law

If distance becomes double, gravitational force becomes:

A Double
B Half
C One-fourth
D One-eighth

Universal gravitational constant G depends on:

A Mass
B Radius
C Temperature
D Nothing

SI unit of G is:

A N
B N·m²/kg²
C Nm/kg
D kg/m²

Weight of body is highest at:

A Equator
B Poles
C Centre of Earth
D Tropic of Cancer

Value of g decreases with:

A Depth below Earth
B Height above Earth
C Both depth & height
D Only rotation

Escape velocity from Earth depends on:

A Mass of body
B Shape of body
C Mass & radius of Earth
D Temperature

Orbital velocity is:

A √(GM/R)
B √(2GM/R)
C GM/R²
D GM/R

Value of acceleration due to gravity at Earth’s centre is:

A g
B 2g
C g/2
D 0

Gravitational potential energy is:

A Always positive
B Always zero
C Always negative
D Always equal to KE

Satellite in circular orbit has:

A Zero KE
B Zero PE
C Constant total energy
D Variable acceleration

Binding energy of satellite is:

A Positive
B Zero
C Negative
D Infinite

For planets, period of revolution obeys:

A Newton’s 1st law
B Kepler’s 3rd law
C Inverse cube law
D Coulomb’s law

Gravitational force between two bodies becomes zero when:

A Distance = 0
B Distance = ∞
C Mass = 0
D Both mass and distance large