Topic Gravitation

Full Marks 30

  1. What is gravitation ? 1
  2. Write and mathematically explain the universal law of gravitation? 2
  3. Write the keplers law of planetary motion? 2
  4. What is free fall? 1
  5. Calculate the force of gravitation due to the earth on a ball of 1kg mass lying on the ground. 3
    (Mass of the earth =6*1024 kg.     radius of the earth = 6.4*103 km. ,G=6.7*1011Nm2/kg2)

Free Test on Motion For Class 9th Physics

  1. Write the Archimedes principle ? 1
  2. Write the difference between Mass and Weight . 3
  3. What is Relative Density? 1
  4. Why is it difficult to hold a school bag having a thin and strong strip?  1
  5. A stone is allowed to fall from the top of tower 100 m high and at rhe same time another stone is projected vertically upwards from the ground with a velocity of 25m/s . calculate when and where the two stones will meet.  3
  6. The weight of Shivanee is 500 N on the Earth. Calculate her mass on the moon? 2
  7. How does a boat float in water? 1
  8. What is buoyancy? 1

Kepler’s Laws of Planetary Motion ,Free Fall and Acceleration Due to Gravity

  1. What is the acceleration due to gravity at a height equal to R/2 from the earth surface? 1
  2. The relative density of silver is 10.8 . Calculate the density of silver?  2
  3. Gravitational force acts on all objects in proportion to their masses . Why then a heavy object does not fall faster than a lighter object? 2
  4. A ball is thrown up vertically returns to the thrower after 6 sec. 3
  5. What is the velocity with which it was thrown up?
  6. The maximum height it reached?
  7. Its position after 4 second?

NCERT Solutions Class 9 Science Force and Laws of Motion