Test Friction

Q. What are the forces acting on a person who is swimming

Q.

Which of the following correctly describes friction?

1. Force that resists the motion of surfaces

2. Force that resists the relative motion of surfaces

3. Force that is magnetic in nature

4. Force that is always in the direction of motion

Q.

Self adjusting force

Q.

Rubbing of hands is what type of friction?

Q.

What is the 'drag' in fluids? [2 MARKS]

Q. The frictional for exerted by fluids is called:
A) drag
B) sliding friction
​​​​​C) rolling friction
D) none of these
​​​​

Q.

What are all the forces acting on a sprinter while running? [2 MARKS]

Q. Static friction is slightly smaller than rolling friction. State true or false.

Q.

The humans can float on water but not walk. Why?

Q. Question 12
The figure shows two boys applying force on a box. If the magnitude of the force applied by each is equal, will the box experience any force of friction?

Q. Frictional force due to fluid is also known as drag.

1. True
2. False

Q. Question 10

Where do we apply a force while walking?

Q.

Arrange the magnitudes of the following in ascending order : Rolling friction, Sliding friction, Static friction.
Also explain why is that? [3 MARKS]

Q. Question 18
The handle of a cricket bat or a badminton racquet is usually rough. Explain the reason.

Q. Does static friction double when the applied force is doubled?

Q. Question 6
Which of the following statements is incorrect?

(a) Friction acts on a ball rolling along the ground.
(b) Friction acts on a boat moving on water.
(c) Friction acts on a bicycle moving on a smooth road.
(d) Friction does not act on a ball moving through air.

Q. Question 19
Explain why the surface of mortar and pestle (silbatta) used for grinding is etched again after prolonged use?

Q. Question 17
While playing tug of war, Preeti felt that the rope was slipping through her hands. Suggest a way out for her to prevent this.

Q. Explain briefly why objects moving in fluids must have special shapes?

Q. Question 14
You might have noticed that when used for a long time, slippers with rubber soles become slippery. Explain the reason.

Q. Question 5
If we apply oil on door hinges, the friction will

(a) increase
(b) decrease
(c) disappear altogether
(d) will remain unchanged

Q.

Why doesn't friction act on the rocket when it is launched immediately ?

Q.

Question 4 (a)
An archer stretches her bow while taking aim at the target. She then releases the arrow, which begins to move towards the target. Based on this information fill up the gaps in the following statements using the following terms:

muscular, contact, non-contact, gravity, friction, shape, attraction

(a) To stretch the bow, the archer applies a force that causes a change in its ___.

Q. Metals can be moulded using heat. The stages that come in the process of moulding iron

1. Put in mould
2. Red hot iron
3. Solidifies
4. Viscous iron
5. Iron melts

Q.

What is static friction? Explain with the help of an example?

Q.

The spikes in the soles of the shoes of athletes, increase friction

1. True
2. False

Q. Why do people sometimes put grease or oil on machine parts to lubricate them?

Q. Question 18
The handle of a cricket bat or a badminton racquet is usually rough. Explain the reason.

Q. Write all the factors that affect fluid friction.

Q.

Why does static friction require highest amount of force compared to rolling or sliding friction