# Applied Physics Past Papers and important Questions

## Applied Physics Past Papers 1

Paper: Applied Physics

Time Allowed:3 hours

Examination:

Total Marks:70, Passing Marks (35)

Q.1 **Fill in the blanks [5]**

- The quantity of matter is known as………….
- Physical quantities can be divide into base and…………quantities.

- If the two vectors A and B have the same line of action then the vectors are called……….vectors.

- To apply the equation of equilibrium, we must account for all the…….and……….forces that act on the particle
- Dry friction occurs between the contacting surfaces of bodies when there is no…………

**Mark True /False [5]**

- The static frictional force F
_{s}generated when sliding occurs at the contacting surface.

- In general, there are three types of mechanics problems involving dry friction.
- Speed is the magnitude of velocity.

- The Instantaneous acceleration(or simply acceleration) a is the second time derivative of velocity v(t).
- Subtraction of vectors may be defined as a special case of the addition of vectors.

**Short answer the following questions. [10]**

- Define weight and how you can derive the formula for weight using Newton’s law of gravitational attraction?
- Convert 2 km/h to m/s. How many ft/s is this?

- Define kinematics and write down the equations of kinematics for constant acceleration.

- A light object and a heavy object have same the momentum. Which has the greater kinetic energy?
- Give some examples of everyday vibrating objects which approximately exhibit SHM.

Q.2 a)What three important idealizations are made in mechanics in order to simplify the application of the theory? [6]

- b) Evaluate each of the following and express with SI units having an appropriate prefix:
- i) (50mN)(6 GN) ii) (400 mm)(0.6 MN)
^{2}iii) 45 MN^{3}/900 Gg . [4]

Q.3 a)Discuss the vector and scalar products in detail. [6]

- b) Vectors
*A*and*B*have scalar product -6 and their vectorproduct has magnitude 9. What is the angle between thesetwo vectors? [4]

Q.4 a) Define the normal and tangential acceleration also derive the expression for normal and tangential acceleration. [6]

b) Find velocity form position given as. [4]

Q.5 In general, there are three types of mechanics problems involving dry friction. Discuss all of them in detail. [10]

Q.6 a) What is a simple pendulum? Show that the motion of simple pendulum is simple harmonic motion. [6]

b)In a meter stick swings about a pivot point at one end, at a distance h from the stick’s center of mass. What is the period of oscillation T? [4]

Q.7 a) Why momentum and impulse are two different physical quantities? Show that momentum is conserved for two-particle isolated systems. [6]

b) What do you mean by instantaneous power? Show that power can be written as dot product of force and velocity. . [4]

Q.8 Write short note on any two of the following [5,5]

- Laws of triangle and parallelogram
- Free body diagram (FBD)

- Types of motion

## Applied Physics Guess Papers 2

Paper: Applied Physics

Time Allowed:3 hours

Examination:

Total Marks:70, Passing Marks (35)

**Q.1** **Fill in the blanks [5]**

- A letter which is used before the unit to represent the power of ten is called………..
- A………vector have always magnitude equal to one.

- A particle is said to be in……………if it remains at rest if originally atrest, or has a constant velocity if originally in motion.

- The tendency to rotate is sometimes called a……….
- The distance of an oscillator from zero displacement to a maximum is called………….

**Mark True /False [5]**

- The coefficient of kinetic friction is always smaller than the coefficient of static friction.

- The rate of change of momentum is called force.
- The acceleration of a body in free fall is always downward.

- The resultant of the product of two vectors is always a vector.
- A force does work when it undergoes a displacementin the direction perpendicular of its line of action.

**Short answer the following questions. [10]**

- Mechanics is divided into two sub branches: Statics and dynamics briefly define these branches.
- Two vectors have length 3.5 Km and 4 Km. what are the maximum and minimum magnitude of their vector sum?

- What do you mean by a free body diagram (FBD)? Draw FBD for a physics book slides on table by with a force F

- Define an isolated system and show that impulse is equal to the change in momentum.
- How work done can be positive, negative and zero when the force and displacement vectors have non-zero magnitudes.

**Q.2** **a)**How the addition of vectors by parallelogram method is different from the addition of vectors by the rectangular components method. ** [6]**

b)Determine the x and y components of F1 and F2 acting on the boom shown in fig. Express each force as a Cartesian vector.[4] |

**Q.3**

**a)** Express the base (fundamental) physical quantities in two different systems of units. **[6]**

**b) **Water has a density of 1.94 slug/ft^{3}. What is the density expressed in SI units? Express the answer to three significant figures. **[4]**

**Q.4** **a)** Define the instantaneous velocity also express velocity in polar coordinates. **[6]**

b)Suppose the x-velocity of the car at any time t is given by the equation (a) Find the change in x-velocity of the car in the time interval 1 s to 3 s. (b) Find the average x-acceleration in this time interval.[4] |

**Q.5 **Discuss the concept of dry friction and show how to analyze the equilibrium of rigid bodies subjected to this force. **[10]**

**Q.6 **

**a) **Define the moment (torque) of a force and also explain the principle of moments (Varignon’s theorem) [**6]**

**b)**Determine the moment of the force in Fig an about point O. [4]

**Q.7 **

**a) **Define the law of conservation of momentum. Show that the rate of change of momentum is equal to force. **[5]**

**b) **Define the free and damped harmonic motion also discuss the motion of a mass attached with a spring. **[5]**

**Q.8 Write a short note on any two of the following **

- Law of solid friction
- Conditions of equilibrium

- Sine and Cosine law.

## Applied Physics Important Question from Past Papers 3

Paper: Applied Physics

Time Allowed:3 hours

Examination:

Total Marks:70, Passing Marks (35)

Q.1 **Fill in the blanks** [5]

- Those physical quantities which are obtained from base quantities are known as………….
- If each term in equation is express in same system of units then the equation is called dimensionally……………
- ……………is the phenomenon in which a very large force is applied for short interval of time.
- The unit of energy in
*cgs*system is………… - The friction force………the tendency of existing relative motion.

**Mark True /False** [5]

- The kinetic frictional force F
_{k}generated when sliding occurs at the contactingsurface. - Power is define as the time rate of doing work.
- Concurrent forces can be balanced by a single force.
- Frequency of second’s pendulum is 2Hz.
- The scalar product of two vectors is always positive.

**Short answer the following questions.** [10]

- Define mechanics and its main sub branches .
- Wood has a density of 4.70 slug/ft
^{3}. What is its densityexpressed in SI units? - Define a couple and what is moment of a couple?
- Define the coefficient of kinetic friction and what is its SI unit?
- Is the acceleration of simple harmonic oscillator ever zero? If so, where?

Q.2 a)What are the basic laws of Newton that are valid in engineering mechanics? [6]

b)If a man weighs 155 lb on earth, specify i) his mass in slugs, ii) his mass in kilograms, and iii) his weight in newtons. If the man is on the moon, where the acceleration due to gravity is g_{m} = 5.30 ft/s^{2}, determine iv) his weight in pounds.

Q.3

a)Explain the system of coplanar and non-coplanar forces with figures [6]

b) Two forces 15N and 12 N are acting at a point. The angle between the forces is 60^{o}. Find the resultant force? [4]

Q.4

a)How will you prove that a body will not be in equilibrium when it is subjected to two forces which are equal and opposite but parallel? [5]

b) Explain with sketches the clockwise and anticlockwise moments [5]

Q.5 What are the laws of limiting friction? Describe an experiment for the verification of the laws of limiting friction. [10]

Q.6

a) Define simple harmonic motion. Show that the motion of mass attached to spring over a frictionless surface is simple harmonic motion. [6]

b) A block whose mass m is 680 g is fastened to a springwhose spring constant k is 65 N/m. The block is pulleda distance x = 11 cm from its equilibrium position atx = 0 on a frictionless surface and released from restatt = 0. What are the angular frequency, the frequency, andthe period of the resulting motion? [4]

Q.7

a) What is collision? How many types of collisions are there? Give example of each. [6]

b) Define power? Show that power is the dot product of force and velocity. Give the cgs and SI units of (i) Work (ii) Power . [4]

Q.8 Write short note on any two of the following [5,5]

- Resolution of a Vector in yz-plane
- Triangle law of forces

- Equation of motion for variable acceleration

## Applied Physics Guess Papers 4

Paper: Applied Physics

Time Allowed:3 hours

Examination:

Total Marks:70, Passing Marks (35)

**Q.1** **Fill in the blanks [5]**

- The branch of physics which concern with the accelerated motion is called……..
- …………….is used to express very large or very small quantities.
- The quantity of motion is called…………
- Speed is the……………of velocity.
- The maximum value of static friction is known as…………..

**Mark True /False [5]**

- Coulomb’s law of friction is friction between dry surfaces.
- In SHM the acceleration is directed toward the equilibrium position.
- The first condition of equilibrium is necessary but not sufficient for equilibrium.
- The rate of change of momentum is called impulse.
- Cross product of two vectors is commutative.

**Short answer the following questions. [10]**

- What do you meant by a free body diagram?
- If a car is traveling at 55 mi/h, determine its speed inkilometers per hour and meters per second.
- State some of the engineering applications of moment.
- Define the coefficient of static friction and what is its SI unit?
- How much work is done by the gravitational force when a 265 kg pile deriver falls 2.8m?

** **

**Q.2**

**a)**Briefly discuss the following terms:

i) Dimensional Homogeneity.

ii) Significant Figures.

iii)Rounding off numbers. **[6]**

**b) **Evaluate each of the following to three significant figures and express each answer in SI units using an appropriate prefix:

i) 354 mg(45 km) / (0.0356 kN) ii) (0.004 53 Mg)(201 ms) **[4]**

**Q.3**

**a) **Define vector and scalar quantities with examples. What do you understand by the term unit vector? What is the importance of the unit vector? **[6]**

**b) **Can a unit vector have any components with a magnitude greater than unity? Can it have any negative components? In each case justify your answer. If where ** a** is a constant, determine the value of “

**” that makes**

*a***a unit vector.**

*A***[4]**

**Q.4**

**a) **Two forces are acting on a body and the body is in equilibrium. What conditions should be satisfied by these two forces? **[5]**

**b) **What is meant by moment of a force? Explain it mathematically. **[5]**

**Q.5 ****a)** What is friction and angle of friction? Prove that the tangent of the angle of friction is equal to the coefficient of static friction. **[6]**

b)The uniform crate shown in has a mass of 20 kg. If a force P = 80 N is applied to the crate, determine if it remains in equilibrium. The coefficient of static friction is µ_{s} = 0.3.[4] |

**Q.6 **

** a) **How do you graphically represent the following? **[4]**

** **(i) Stationary object (ii) Uniform motion (iii) Accelerated motion

**b)**What is cross product? Describe different properties of cross product of vectors. **[6]**

**Q.7 **

**a****) **State the following laws of forces? **[5]**

** **(i) Parallelogram law (ii) Triangle law

**b) **Prove that the work done in moving a body of mass m up a frictionless inclined plane of inclination θ and height h is equal to *mgh*. . **[5]**

**Q.8 **Write short note on any two of the following** [5,5]**

- Simple harmonic motion
- Impulse of constant and variable force.

- Normal and Tangential acceleration