Natural Resources — Science STD 9 — Question

Name the part of the ear:

connects the pinna with eardrum.

What is the actual shape of the orbit of a planet around the sun? What assumption was made by Newton regarding the shape of an orbit of a planet around the sun for deriving his inverse square rule from Kepler’s third law of planetary motion?

The echo of a sound is heard after 5 seconds. If the speed of sound in air be 342m/s, calculate the distance of the reflecting surface.

1. Distance covered by the scooterist.
2. Displacement of the scooterist.
3. Time taken by the scooterist in reaching from A to B.

If 784J of work was done in lifting a 20kg mass, calculate the height through which it was lifted. (8 = 9.8m/s²)