When to Call It a Pure Translation

Q. A box is being pushed on a horizontal surface. What kind of motion it performs?

1. Pure translation
2. pure rotation
3. Pure rotation and translation
4. neither pure rotation nor pure translation

Q. Which of the following statements is incorrect?

1. A fan is rotating about a fixed axis then net torque on the fan may be zero.
2. Moment of inertia of particle about an axis depends on perpendicular distance from the axis.
3. For equilibrium of a rigid body net force & net torque must be zero.
4. For a large cubical box sliding down a rough inclined plane normal force on box must pass through center.

Q.

A corkball and a tennis ball have same size and shape. Both are pressed with same force. This compresses the tennis ball but the cork ball is not compressed at all. Which of the following statement is true from the above context?

1. Cork Ball is rigid-body but tennis ball is a non-rigid body.

2. Tennis ball is rigid-bodybut cork ball is a non-rigid body

3. Both are rigid body

4. Both are non-rigid body

Q.

Which of the following is/are necessary and sufficient condition(s) for pure translation?

1. The relative position of particles of the body does not change with time.

2. Velocities of all the particles are parallel to each other at any given instant.

3. A body always remains parallel to itself throughout its motion.

4. Velocities of all the points of the body at any instant of time are equal.