Surface Irregularities

Q. The surface of the conveyor belt is made rough and tight so that the object placed on it doesn't slips when the belt moves or stops.

1. False
2. True

Q. A rough surface will offer more frictional force to any object moving over it as compared to a smooth surface.

1. True
2. False

Q.

Arrange the following in increasing order of surface roughness:

• Sandpaper
• Polished steel
• Cardboard

1. Cardboard < Sandpaper < Polished steel
2. Polished steel < Sandpaper < Cardboard
3. Sandpaper < Cardboard < Polished steel
4. Polished steel < Cardboard < Sandpaper

Q.

A cube is pushed in such a way that it is sliding on a horizontal surface. Frictional force acting on the cube can be increased by:

1. Adding wheels to the cube.

2. Applying lubricant between the cube and the surface.

3. Polishing the outer surface of the cube.

4. Placing another identical cube on top of the cube.

Q.

Consider the following statements:

Statement 1: Irregularities on two surfaces lock into one another.

Statement 2: We have to apply a force to overcome the interlocking so as to move any of the two surfaces in contact.

Choose the correct option:

1. None of the statements are correct

2. Only Statement 2 is correct

3. Both the statements are correct

4. Only Statement 1 is correct

Q.

Consider the following statements:

Statement 1: Friction is caused by the interlocking of irregularities in the two surfaces.

Statement 2: The force of friction will increase if the two surfaces are pressed hard against each other.

Choose the correct option:

1. Non contact force

2. Contact force

3. Muscular force

4. Electrostatic force

Q.

What is the cause of friction?

Q. Which of the following objects offers less friction?

1. Plywood
2. Silk cloth
3. Tree bark
4. Sand paper

Q. When a soft surface deforms and opposes motion of a body sliding on it, this is known as .

1. adhesion
2. roughness
3. plowing effect
4. interlocking

Q.

A ball is rolled on sand, on a cemented road and on an ice platform. In which of these cases will it move the farthest?

1. Sand

2. Same on all cases

3. Road

4. Ice

Q. the friction Coefficient between an athletes shoes and the ground is. 9 suppose a Superman wears these shoes and races for 50 metres. there is no upper limit on his capacity of running at high speed. find the minimum time that he will take in completing 50 metre from starting from rest. suppose he takes exactly this time to complete the 50 metres. what minimum time will he take to stop?

Q.

Asha runs her toy car on a dry floor, wet floor, newspaper spread on the floor and on a towel spread on the floor. What will be the force of friction in increasing order acting on the car on different surfaces.

Q. If a body is sliding over another, their interlocked irregularities___ relative motion.

1. support
2. cancel
3. oppose
4. suppress