Ch 5 Phy Class 9
Important Easy Notes of Ch 5 Phy Class 9 English Medium written by Professor Mr. Samiullah Suib. These notes are very helpful in the preparation of Physics for students of the 9th class Physics English Medium and these are according to the paper patterns of all KPK Book Boards.
Summary and Contents:
Topics which are discussed in the notes are given below:
- Definition of Gravitation: symbol, Unit, Quantity, Nature and Explanation, Factors and Examples.
- Definition of gravity
- Law of universal gravitation: History, Propose, Statement, Mathematical form, Applications.
- Newton's third law of motion and universal gravitation.
- Graphical analysis of gravitational force.
- Mass of Earth
- Definition of gravitational field with explanation.
- Definition of gravitational field strength: symbol, mathematical form, quantity, unit, explanation.
- Variation in weights with location.
- Definition of gravitational acceleration: symbol, and value explanation.
- Variation of G with altitude.
- Why the value of " g " at the pole is greater than the at equator?
- Definition of satellites and Causes of motion
- Types of satellites: (i) neutral satellites (ii) artificial satellites.
- Definition of neutral satellites with examples.
- Definition of artificial satellites with examples.
- Importance of artificial satellites.
- Definition of Orbital speed: symbol, mathematical form, derivation.
- Calculation of Orbital speed for Geostationary Communication Satellite.
- If there is an attractive force between all objects why do not we feel ourselves gravitating toward nearby massive building?
- Does the sun exert a larger force on the earth then exited on the sun by Earth? explain.
- What is the importance of gravitational constant "G" ? Why is it difficult to calculate?
- If Earth somehow expanded to a larger radius, with no longer change in mass, how would you wait be affected? How would it be affected if earth instead shrunk?
- What would happen to your weight on the Earth if the mass of the earth doubled but its radius stayed the same?
- Why lighter and heavier objects fall at the same rate towards Earth?
- The value of " g " changes with the location on earth, however we take same value of " g " at 9.8 ms^-2 for ordinary calculations. Why?
- Moon is attracted by the earth does not fall on earth?
- Why for same height larger and smaller satellites must have same orbital speeds?
- Solved Numerical of the exercise Ch 5 Phy Class 9.
- Pluto's moon Charon is un-usually large considering Pluto's size giving them the character of a double planet. Their masses are 1.25*10^22kg and 1.9*10^21kg and their average distance from one another is 1.96*10^4km. What is the gravitational force between them?
- Titan is the largest moon of the Saturn and the only moon is in the solar system are known to have a substitutional atmosphere. Find the acceleration due to gravity on the Titan's surface given that its mass is 1.35*10^18 kg and its radius is 2570km.
- Assume that a satellite orbits Earth 225km about its surface. Given that the mass of the Earth is 6*10^24 kg and the radius of the earth is 6.4*10^m, what is the satellite is orbital speed?
- The distance from the centre of the earth to centre of moon is 3.8*10^8m, Mass of Earth is 6*10^24 kg. What is the orbital speed of the motion?
- The Hubble space telescope orbits Earth with an orbital speed of 7.6*10^3 m/s. Calculate its altutude above Earth's surface.