Machine Dynamics Interview Questions & Answers

Question 1. What Is Meant By Dynamics?

Answer :

The study of motion, which describes a relation between force and its effect, is called dynamics.

Question 2. What Is Force?

Answer :

It is an effort which sets the objects in motion.

Question 3. What Is Intertia?

Answer :

The property of a material body by virtue of which the body at rest tends to remain at rest and an object in motion tends to remain in motion is called interia.

Bodies have two kinds of intertia :

1.  Interia at rest
2.  Intertia of motion 

Question 4. How Is Interia Related With Mass Of The Body?

Answer :

A quantitative measure of the property of interia of an object is its mass. Greater the mass of the body, larger is the effort needed to set it in motion. Also greater the mass of a body, the larger is the effort needed to stop it if it is in motion already.

Question 5. What Is A Force Field?

Answer :

It is region where at every point, the magnitutde and the direction of the force is known.

For example: the gravitational force due to the earth acting on a mass of 1kg can be specified at all the points on the surface of earth both in magnitude and direction. We then say that there is a gravitational “ force field ”

Question 6. Who Helped To Found The New Science Of Thermodynamics, Establishing Clear Relationship Between Heat, Work And Energy?

Answer :

Lord Kelvin

Question 7. Which Are The Basic Types Of Forces?

Answer :

1.  Gravitational force
2.  Electrostatic force
3.  Magnetic force
4.  Atomic force
5.  Nuclear force

Question 8. What Is Gravitational Force?

Answer :

There is a gravitational force of attraction between any two objects. All objects fall towards the earth because of gravitational force of earth, F= mg, where m is mass of the body. The direction of this force is towards the centre of the earth. This force is effective over large distances.

Question 9. What Is The Electrostartic Force?

Answer :

There are two types of charges; positive and negative. The electrostatic force between two opposite charges is attractive while between two similar charges it is repulsive. This force is effective over large distances.

Question 10. What Is Magnetic Force ?

Answer :

The force between two magnets is called magnetic force. The electric and magnetic forces are two facts of the general electromagnetic force facts.

Question 11. What Is Atomic And Nuclear Forces?

Answer :

With the help of these forces we can explain he observations made on atoms and nucleons. These observations can be explained on two types of forces called strong and weak forces. Strong force acts between protons and neutrons in a nucleus. It acts only over a very short range of about 10 -15 m. A weak force acts between any two elementary particles like electron and neutron.

Question 12. A Horse Cannot Pull A Cart And Run In Empty Space.why ?

Answer :

Because there is no friction in empty space.

Question 13. Passengers Are Thrown Forward From Their Seats When Speeding Bus Stops Suddenly?

Answer :

This is because if inertia of motion.

Question 14. State The Law Of Conservation Of Momentuem?

Answer :

When two or more bodies interact with one another, their total momentum remains constant, provided no external forces are acting.

Question 15. What Is Force Of Friction?

Answer :

When a solid body is moved over the surface of another solid body, an opposing force acts in between the two surface ( parallel to them ) and it tends to destroy the relative motion in between them. This opposing force is called force of friction. The magnitude of the force of friction depends upon the nature of the two surfaces in contact.

Question 16. Why Are The Types Of Vehicles Retreaded If They Become Smooth?

Answer :

Rolling of a wheel on surface is possible because of the friction between the two. Due to this reason the types have treads which increase friction and avoid slipping.

Question 17. What Is Meant By Rolling Friction ?

Answer :

The frictional force between two surfaces when one roles over the other is called rolling friction. A wheel or a ball is slightly flattened when its rests over a surface. A surface also is slightly dented. Because of this deformation a resistance force arises when the wheel or ball rolls on a surface. This is called rolling friction. Rolling friction is much smaller than sliding friction.

Question 18. An Astronau Just Releases A Spoon Out Of His Spaceship Acclerating In The Interstellar Space At A Constant Rate Of 100 M / S ². Then The Acceleration Of The Spoon At The Instant When It Is Thrown Outside Is?

Answer :

Zero.

Question 19. A Stone Tied At The End Of A Rope Is Being Whirled In A Horizontal Circle. Suppose The String Breaks Then?

Answer :

The stone moves towards the centre of the circular path.

Question 20. Newton’s Second Law Of Motion Relates?

Answer :

Force and velocity

Question 21. If Two Objects Have Equal Momenta, Then?

Answer :

The lighter objects is moving faster than heavier.

Question 22. When A Force Acts On A Body In Its Direction Of Motion Then The Momentum?

Answer :

Keeps on increasing.

Question 23. The Motion Of A Billiard Ball Or Carom Coin Represents The Motion Of?

Answer :

Two dimensions.

Question 24. Which Motion’s Do All The Objects That Move On Earth’s Surface Over Distances Comparable To Earth’s Diameter Possess ?

Answer :

Two dimensional motion.

Question 25. If The Particles Move With Same Velocity And Their Paths Are Parallel, Their Motion Is Called?

Answer :

Translatory and rotatory motion.

Question 26. Which Is Called A Rotatory Motion ?

Answer :

When a body rotates about a fixed axis the motion is said to be rotatory.

Question 27. What Is Displacement ?

Answer :

Displacement is the vector that specifies the change in position of a point or a particle in reference to a previous position. When the previous point is the origin, this is better referred to as a position.

Question 28. The Heat Added To A System Is Equal To?

Answer :

A change in its internal kinetic energy, potential energy.

Question 29. Which Is The Force That Makes The Car Go Straight?

Answer :

Centrifugal force

Question 30. Which Force Causes Weightlessness In Orbit ?

Answer :

Centripetal force

Question 31. When An Object Is In Equilibrium Or Balanced The Turning Force On One Side Of The Fulcrum Is Equal To The?

Answer :

Turning force on the other side.

Question 32. Who Used Turning Forces To Weigh Things In Ancient Time ?

Answer :

Romans

Question 33. The First Law Of Thermodynamics Is Concerned With The Conservation Of ?

Answer :

Energy 

Question 34. What Does The First Law Of Thermodynamics Confirm ?

Answer :

It confirms the law of conversion of energy.

Question 35. No Heat Engine Can Be 100 % Efficient ”. Which Law Implies This ?

Answer :

The second law of thermodynamics.

Question 36. What Is The Principle Of The Working Of A Rocket ?

Answer :

Conservation of momentum

Question 37. Who Was The First Person To Formulate The Laws Concerning Rest And Motion ?

Answer :

Isaac Newton.

Question 38. A Bomb Is Dropped From An Aircraft When It Is Directly Above A Target At A Height Of 1000 Metre. The Aircraft Is Moving With A Velocity Of 500 Km / Hour. Will The Bomb Hit The Target ?

Answer :

The bomb will not hit the target. The bomb wil strike at a point 1982 metre away from the target. 

Question 39. What Is A Force?

Answer :

It is defined as the external agency that changes or tends to change the state of rest or uniform motion of a body in a straight line.

Question 40. Which Are Newton’s Three Laws Of Motion ?

Answer :

1. A body continues in a state of rest or of motion at constant speed in a straight line, except when this state is changed by forces acting on it.
2. Force is equal to mass multiplied by acceleration.
3. For every action there is equal and opposite reaction.

Question 41. A Rocket Works On The Principle Of Conservation Of Momentum. It Follows From Which Law ?

Answer :

Newton’s third law.

Question 42. What Is The Energy Of A Body Is Defined As ?

Answer :

It is defined as its capacity to do work.

Question 43. Which Are The Main Forms Of Energy In Physics ?

Answer :

Heat, Light, Sound, Magnetic, Electric, Kinetic, Potential etc,, are the main forms of energy.

Question 44. What Are Allotropes ?

Answer :

They are different physical structures of a solid substance,

Example: diamond and graphite both are, allotropes of carbon.

Question 45. What Is Called The Crystallography ?

Answer :

It is the method used to study the structure of crystals.