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9th Class Examination 2015 Physics important Question / Notes Chapter 1 to 5

1. Define Mechanics and Geophysics.

2. Estimate your age in seconds.

3. Define significant figures with example.

4. Differentiate between mechanical and digital stop watch.

5. How we can find out the least count of screw guage?

6. Write the numbers given below in scientific notation.

(a) 3000000000 ms-1 (b) 6400000 m

(c) 0.0000000016 g (d) 0.0000548s

7. Write down the base quantities, their SI units with symbols.

8. How do the prefixes micro, nano and pico relate to each other?

9. What is the difference between base quantities and derived quantities? Give two examples in each case.

10. What is meant by vernier constant?

Long Question

1. (a) Write down the rules to find out the significant digits in a measurement?

(b) A chocolate wrapper is 6.7cm long and 5.4 cm wide. Calculate the area up to reasonable number of significant figures.

1. Differentiate between circular motion and rotator motion also gives its example.

2. Give an example of a body at rest and in motion at the same time.

3. Define acceleration; write its formula and unit.

4. A sprinter completes its 100 meter race in 12s. Find its average speed?

5. Why vector quantities cannot be added and subtracted like scalar quantities?

6. Differentiate between uniform acceleration and uniform velocity.

7. Can a body move at constant speed have acceleration?

8. What would be the shape of a speed-time graph of a body moving with variable speed?

9. A bicycle accelerates at 1 ms-2 from an initial velocity of 4 ms-1 for 10s. Find the distance moved by it during this interval of time?

10. Define random and linear motion with examples.

Long Questions 5×1=5

1. (a) Prove that S= Vit+1/2at2. 2.5

(b) A car has velocity of 10 ms-1. It accelerates at 0.2 ms-2 for half minute. Find the distance travelled during this time and the final velocity of the car? 2.5

1. Differentiate between mass and weight.

2. Find the acceleration that is produced by a 20 N force in a mass of 8 kg?

3. Why is it dangerous to travel on the roof of a bus?

4. Action and reaction are always equal and opposite then how a body does moves?

5. Describe ways to reduce friction.

6. Define force and also define its unit.

7. How does the dryer of a washing machine work on the principle of centripetal force?

8. What is the law of conservation of momentum? Give its examples.

9. A force of 20 N moves a body with an acceleration of 2ms-2. What is its mass?

10. State the Newton’s third law of motion with examples.

Long Questions 5×1=5

1. (a) State and explain the Newton’s Second law of motion. 2.5

(b) How much centripetal force is needed to make a body of mass 0.5 kg to move in a circle of radius 50cm with a speed 3ms-1? 2.5

1. What do you mean by resolution of forces and perpendicular components?

2. Define clockwise and anticlockwise moments with examples.

3. Think of a body which is at rest but not in equilibrium.

4. Differentiate between torque and couple.

5. A force of 100 N is applied perpendicularly on a spanner at a distance of 10cm from a nut. Find the torque produced by the force?

6. Define torque; on what factors does the torque depend?

7. Define centre of mass and centre of gravity.

1. State the law of gravitation.

2. What is GPS and what is its function?

3. Why earlier scientist could not guess about the gravitational force?

4. What are artificial satellites and what are their functions?

5. Why does the value of g vary from place to place?

6. Why law of gravitation is important to us?

7. Do you attract the Earth or the Earth attracts you? Which one is attracting with a larger force?

8. Why communication satellites are stationed at geostationary orbits?

9. What is a field force?

10. Why we do not feel the force of attraction between the objects?

Long Questions 5×1=5

1. (a) How the mass of Earth can be determined. Explain. 3

(b) Find the gravitational force of attraction between two spheres each of mass 1000 kg. The distance between the centers of the sphere is 0.5m? 2

8. What is meant by neutral equilibrium? Give at least one example.

9. A block of weight 10N is hanging through a cord. Find the tension in the cord?

10. Define equilibrium and stable equilibrium.

Long Questions 5×1=5

1. (a) Write a note on states of equilibrium with examples. 3

(b) Find the perpendicular components of a force of 50N making an angle of 300 with x-axis? 2