Tag: moving through fluids

Quizzes (0) Questions (25)

Questions Related to moving through fluids

Multiple choice physics dynamics - explaining motion air resistance fluid friction moving through fluids

Fill in the blanks 
Dynamic Fluid friction is _______ the sliding friction of solids.

  1. heigher than

  2. lower than

  3. same as

  4. higher than or equal to
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Friction is the force that opposes motion between any surfaces that are in contact. There are four types of friction: static, sliding, rolling, and fluid friction. Static, sliding, and rolling friction occur between solid surfaces. Fluid friction occurs in liquids and gases.

The maximum limit of static friction is called limiting friction . So,the coefficient of static friction is usually more than that of sliding or kinetic friction. ... Static friction is greater because it works when two surfaces in contact are just to start a relative motion or are in rest.

Multiple choice physics dynamics - explaining motion air resistance fluid friction moving through fluids

The frictional force exerted by fluids is called:

  1. lift

  2. drag

  3. rolling friction

  4. dynamic friction
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Lift is the upward acting force which is against gravity. Drag is the resistance force or friction force in fluid. The rolling friction is a resistive friction when a body rolls on a surface. The dynamic friction is the friction that must be overcome to maintain steady motion of one object relative to another because they remain in contact.

Multiple choice physics dynamics - explaining motion air resistance fluid friction moving through fluids

Boats and aeroplanes are ................. so as to reduce fluid friction.fill in the blank.

  1. large

  2. broader

  3. streamlined

  4. bigger
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Boats and aeroplanes are streamlined so as to reduce fluid friction.
Aeroplanes, boats, fishes and birds which move through fluids have bodies of special shape, called streamlined shape, so as to reduce the friction due to fluid and avoid energy loss. 
For example,if the boat isn't streamlined, then it also has to push the water out of its way, increasing the drag force.

Multiple choice physics dynamics - explaining motion air resistance fluid friction moving through fluids

Fluid friction depends on ______

  1. speed of the object

  2. shape of the object

  3. nature of fluid

  4. all of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The speed of the object moving through a fluid affects the amount of friction acting against the motion of the object. More the speed, more is the friction. If the object is broad, it gives more area for the friction to act on. Thus, a streamlined body structure helps to cut through the fluid and reduce friction. Also, the nature of the fluid affects friction.

Multiple choice physics dynamics - explaining motion air resistance fluid friction moving through fluids

What measures are taken to reduce fluid friction in aeroplanes?

  1. Optimum speed is maintained with respect to the air

  2. Metals are choosen in a way to make the aeroplane lighter with smoother surface

  3. Streamlined body inspired by birds

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

It is very important to minimize fluid friction for aeroplanes because more friction for aeroplanes may produce more heat, which may harm the plane. Thus, various measures are taken to reduce friction. An optimum speed is maintained and the body structure of the plane is more streamlined so that it can cut through air with minimum friction. Also, such metals are chosen which are light but strong and also make for smooth surface.

Multiple choice physics dynamics - explaining motion air resistance fluid friction moving through fluids

To move at same speed, a car with flat face and another with streamlined body, will require different amount of force from the engine. The engine of the streamline bodied car will:

  1. exert less force

  2. exert more force

  3. exert zero force

  4. exert no force
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A car with streamline body suffers less air friction while moving. And the car with flat face will suffer higher air friction. As a result, the car with streamline body will require less force from the engine to maintain the same speed.

Multiple choice physics dynamics - explaining motion air resistance fluid friction moving through fluids

While the arrow moves towards its target, the force acting on it are due to gravity and due to ____ of air.

  1. gravitational force

  2. muscular force

  3. magnetic force

  4. frictional force
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When the arrow moves toward target, the force acting on it, is due to gravity and resistive force of air. The resistance force of air is also called as frictional force.