# Physics 9 Solved Paper 2016 Federal Board

**Class 9 Physics Solved Paper 2016**

Class 9 Physics Solved Paper 2016 for Federal Board is available in this post. You can see more FBISE solved past papers of class 9 on our website.

**Class 9 Physics Solved Paper 2016**

**Section A**

**Q1. MCQs **

**Class 9 Physics Solved Paper 2016**

**Section B**

**Class 9 Physics Solved Paper 2016**

**Q2. **

**(i) ****What is meant by Mechanics and Geophysics?**

**What is meant by Mechanics and Geophysics?****Excluded from Syllabus for Annual Exam 2021**

**(ii) **An object starts from rest. Write down changed equations for the motion of the object.

**Ans. **For an object that starts from rest vi = 0

Now first equation of motion is

vf = vi + at

Putting vi = 0

vf = 0 + at**vf = at **

The second equation of motion is

S= vi t+½ at^{2}

Putting vi = 0

S = (0) t+ ½ at^{2}**S = ½ at ^{2}**

The third equation of motion is

2aS = vf

^{2}– vi

^{2}

Putting vi = 0

2aS = vf

^{2}– (0)

^{2}

**2aS = vf**

^{2}**(iii) **Define centripetal force and also give its formula.

**Ans. Centripetal Force**Centripetal force is a force that keeps a body moving in a circle. It always acts perpendicular to the motion of the body. It is denoted by F

_{c}.

**Formula:**F

_{c}= mv

^{2}/ r

**(iv) **Differentiate between ‘g’ and ‘G’.

**Ans. **The ‘g’ is the acceleration due to gravity produced in a free-falling body due to the attraction of the earth. Its value is 9.8 ms-2 on the surface of the earth. Whereas ‘G’ is the gravitational constant and its value is 6.67×10^{-11} Nm^{2}kg^{-2}.

**(v) **How much time is required to change 22 Ns momentum by a force of 20N?

**(vi) **Why is the base of a vehicle made wide?

**Ans.** The base of a vehicle is made wide so that the vertical line passing through its centre of gravity should not get out of its base during a turn. This is done to avoid over-turning of vehicles during turning.

**(vii) **Briefly describe that law of gravitation is consistent with Newton’s third law of motion.

**Ans.** Consider two masses m_{1} and m_{2} such that mass m_{1} attracts m_{2} towards it with a force F while mass m_{2} attracts m_{1} towards it with a force of the same magnitude F but in opposite direction. If the force acting on m_{1} is considered as action then the force acting on m_{2} will be the reaction. The action and reaction due to force of gravitation are equal in magnitude but opposite in direction. This is consistent with Newton’s third law of motion which states, to every action there is always an equal but opposite reaction.

**(viii) **Name and define the unit of power.

**Sol. Unit OF Power**

SI unit of power is ‘watt’. The power of a body is said to be one watt (1 W) if the work done by it is one Joule in 1 second.

Bigger units of power are:

1 kW = 10^{3} W = 1000 W

1 MW = 10^{6 }W = 1000,000 W

1 horse power 1 hp = 746 W

**(ix) **State Pascal’s Law.

**Ans: Pascal’s Law**

This law states that pressure exerted from outside on a liquid is transmitted equally in all directions. This law has some useful applications.

1. **Hydraulic press** is used to compress raw cotton and cloth into bails.

2. This law is used in **Hydraulic brake systems** and in other hydraulic machines.

3. This law is also used at the service stations to lift the cars for washing.

**(x) Calculate the coefficient of linear thermal expansion of aluminum if the value of its coefficient of volume expansion is 7.2 x 10**^{-5} K^{-1}.

^{-5}K

^{-1}.

**Sol.** Coefficient of volume expansion of aluminum = β = 7.2 x 10^{-5} K^{-1}

Coefficient of linear thermal expansion of aluminum = α =?

Since β = 3 α

or α = β / 3

α = 7.2×10^{-5} / 3

α** = 2.4 × 10 ^{-5} K^{-1}**

**(xi) A cup of hot tea becomes cold after sometime. Why?**

**Excluded from Syllabus for Annual Exam 2021**

**(xii) **Draw a temperature-time graph showing the change of state of ice into water and steam.

**Excluded from Syllabus for Annual Exam 2021**

**(xiii) **What is an Atwood machine?

**Excluded from Syllabus for Annual Exam 2021**

**(xiv) ** Define centre of gravity.

**Ans. Centre of gravity**

A point where the whole weight of the body appears to act vertically downward is called centre of gravity of a body. For example, the centre of gravity of a uniform triangular sheet is the point of intersection of its medians.

**(xv) ** Define Stress. Also give its formula and unit.

**Ans.** **Stress**

Stress is related to force producing a deformation. It is defined as “the force acting on a unit area at the surface of a body is called stress.” Thus,

Stress = Force / Area

In SI, the unit of stress is newton per square metre (Nm^{-2}).

### **Class 9 Physics Solved Paper 2016**

**Section C**

**Class 9 Physics Solved Paper 2016**

#### Attempt any TWO questions. All questions carry equal marks.

**Q3. a. State and explain that law of conservation of momentum. (****1+4)**

**1+4)**

**Ans. Law of Conservation of Momentum**

Law of Conservation of momentum states that “The momentum of an isolated system of two or more than two interacting bodies remains constant.”

Consider an isolated system of two spheres of masses ‘m1’ and ‘m2’ moving with velocities ‘u1’ and ‘u2’ respectively in the same direction. If u1> u2, the two spheres will collide with each other. Let their velocities become ‘v1’ and ‘v2’ respectively after the collision.

Thus,

Total momentum before collision = m_{1}u_{1} + m_{2}u_{2}

Total momentum after collision = m_{1}v_{1} + m_{2}v_{2}

According to the law of conservation of momentum

m_{1}u_{1} + m_{2}u_{2} = m_{1}v_{1} + m_{2}v_{2}

** Q3. b. Graphically prove that 2aS = vf**^{2} – vi^{2} (5)

^{2}– vi

^{2}(5)

** Q4. a. Define equilibrium and explain the first condition for equilibrium. (****1+3)**

**1+3)**

**Ans. Equilibrium**

A body is said to be in equilibrium if no net force acts on it.**Examples: **

A book lying on a table or a picture hanging on a wall **First Condition for Equilibrium**

According to this condition, a body is said to be in equilibrium if the sum of all the forces acting along any straight line on a body is zero.

Let ‘n’ number of forces F1, F2, F3,.…,Fn are acting on a body such that

F1+F2+F3………….+Fn = 0

or ƩF= 0

or ƩFx = 0 and ƩFy = 0

Then the body is said to satisfy the first condition of equilibrium.

** Q4. b. A man has pulled a cart through 35 m applying a force of 300N. Find the work done by the man. (****3)**

**3)**

**Sol.** Force = F = 300 N

Distance = S = 35 m

Work done = W =?

Using formula

W = F x S

W = 300 x 35**W = 10500 J**

** Q4. c. Describe Einstein’s Mass-Energy equation. (****3)**

**3)**

**Excluded from Syllabus for Annual Exam 2021**

** Q5. a. Describe the scales of temperature. Give Formulas for the conversion of temperature from one scale to the other. (****3+3)**

**3+3)**

**Excluded from Syllabus for Annual Exam 2021**

** Q5. b. The acceleration due to gravity on the surface of the moon is 1.62 ms**^{-2}. The radius of the moon is 1740 km. Find the mass of the moon. (4)

^{-2}. The radius of the moon is 1740 km. Find the mass of the moon.

Good effort.

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