Viva Voce: Relationship Between Weight of a Body and Force Required to Just Move it | Lab Manuals for Class 9 PDF Download

Q.1.Why is it necessary for a particular weight to be placed to move the block?

To overcome the friction between the block and the table.

Q.2. Does the value of the contact area affect your result? Give reason.

No, friction does not depend on area of contact.

Q.3. Why is the tension on the vertical and horizontal string equal?

The string is incompressible, inextensible and massless. So, the tension will be the same at both the sides.

Q.4. What is limiting friction?

The maximum value of force of friction which prevents the block from moving is called limiting friction.

Q.5. Will your result hold good if the string is heavy?

No, as the tension varies from point to point in the string if it is heavy.

Q.6. Is friction experienced by the block a constant force?

No, it increases from zero to a particular value equal to the weight at which the slab slides.

Q.7. What is the SI unit of tension?

Newton, as tension is a force.

Q.8. Can a mass be moved using a string which is not taut?

No, taut string has tension.

Q.9. Why does the block not move if we pull the spring balance with less force?

Due to the presence of friction on the block.

Q.10. In what way dust affects our reading?

Dust increases the friction.