Environmental Management — Science STD 9 — Question

A coin is kept in front of two plane mirrors inclined to each other. If 3 images of the coin are seen then what is the angle A between the mirrors?

Meristematic tissue.

Explain recoil and recoil velocity. Derive its expression.

Write short note : principles of first aid

What is meant by co-ordination?

1. Take two aluminium channels of different lengths.
2. Place the lower ends of the channels on the floor and hold their upper ends at the same height.
3. Now take two balls of the same size and weight and release them from the top end of the channels. They will roll down and cover the same distance.

Questions
1. At the moment of releasing the balls, which energy do the balls have?
2. As the balls roll down which energy is converted into which other form of energy?
3. Why do the balls cover the same distance on rolling down?
4. What is the form of the eventual total energy of the balls?
5. Which law related to energy does the above activity demonstrate? Explain.

Why do doctors advise you to take yoghurt or buttermilk if you have indigestion or abdominal discomfort?

symbols of the elements you know.