Drag Force

Q.

Question 10
Explain why objects moving in fluids must have special shapes.

Q.

The fast-moving vehicles are given a streamlined shape. Why?

Q.

What is the special name of frictional force exerted by fluids (like air or water)?

Q. DerivAtion of kinetic energy of rolling motion

Q.

(a) What is the drag? Give two examples for a drag force.
(b) How can you reduce the drag on something moving through the air?

Q.

(a) What do you meant by 'streamlined shape'? Name an object which usually has a streamlined shape.
(b) Explain why, objects moving in fluids should have streamlined shape.

Q.

What is the name of 'special shape' which is given to objects moving through the air (or water) to reduce drag?

Q.

What is the frictional force exerted by fluids on objects moving through them known as?

1. Weight

2. Lift

3. Thrust

4. Drag

Q.

How do you tell if youre negative buoyant?

Q.

Explain why, a speedboat has a streamlined shape.

Q. How does a cat not hurt itself on jumping or falling from a height?

1. It has soft skin so when it falls, it won’t get hurt
2. It spreads its legs wide apart and increases air drag
3. It brings its legs closer so that force is evenly distributed when it lands
4. It uses its tail to save itself

Q.

What would fall quicker, a feather or a hammer? Why?

Q.

Frictional force depends on

1. Coefficient of friction

2. Weight of the body

3. Normal reaction

4. Volume of the body

Q. Friction is a type of a __________ force which opposes the__________ between two surfaces.

1. contact, pressing force
2. non-contact, relative motion
3. non-contact, pressing force
4. contact, relative motion

Q. A wheel has been described as one of the greatest invention of man. Why?

Q. The frictional force exerted by a fluid is called:
(a) brag
(b) drab
(c) drag
(d) tread

Q. Friction is a type of a __________ force which opposes the__________ between two surfaces.

1. non-contact, relative motion
2. contact, relative motion
3. non-contact, pressing force
4. contact, pressing force

Q.

if gravitational force is acting on every object present on earth then why aeroplane is able to fly why dont it get crashed ot land.

Q.

In which state of matter is the friction the greatest i.e. friction in which State of matter causes most resistance.Plz. explain.

Q. Considering no air drag, if a ball starts moving on a frictionless horizontal surface, it will:

1. never stops
2. stops after long duration
3. stops after short duration
4. cannot be determined

Q. A block is sliding with constant speed. Identify the correct statement regarding frictional forces on the block.
Statement 1: Friction offered by ground increases as the speed of the block increases.
Statement 2: Drag increases as the speed of the block increases.

1. Only Statement 1 is correct.
2. Both the statements are correct.
3. Only Statement 2 is correct.
4. None of the statements are correct.

Q.

An aeroplane flying in the atmosphere experiences no friction.

1. True

2. False

Q. Identify the type of friction acting on the object given in the figure:

1. Static friction
2. Rolling Friction
3. Sliding Friction
4. Fluid Friction

Q. Air drag _____ on increasing surface area.

1. increases
2. decreases
3. None of the above
4. doesn't affect

Q. Frictional force on a moving object in a fluid depends on :
(i) Shape of the object
(ii) Mass of the object
Choose the correct one.

1. Only (ii) is correct
2. Both (i) and (ii) are correct
3. Both (i) and (ii) are incorrect
4. Only (i) is correct

Q.

A coin and a feather are dropped from the roof of a building. Which one will fall to the ground first?

Q. When a submarine moves through water, it experiences:

1. kinetic friction
2. static friction
3. rolling friction
4. fluid friction

Q.

Fast moving vehicles are designed to have streamlined shapes.

1. True

2. False

Q. Friction is a type of a __________ force which opposes the__________ between two surfaces.

1. contact, relative motion
2. non-contact, pressing force
3. non-contact, relative motion
4. contact, pressing force

Q.

What is the frictional force exerted by fluids on objects moving through them known as?

1. Lift

2. Thrust

3. Weight

4. Drag