Tag: physics

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Questions Related to physics

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.  

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

If we drop a cup of water on a plate and a cup of oil on another plate, water is seen to spread faster along diameter. This is an example related to:

  1. fluid friction

  2. rolling friction

  3. sliding friction

  4. static friction
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This example relates to fluid friction. Speed of spreading of a volume of liquid depends on the liquid friction.Friction offered by water is less as its density is less than oil.