The Fundamental Unit of Life — Science STD 9 — Question

A driver of a car travelling at 52km/ h⁻¹ applies the brakes and accelerates uniformly in the opposite direction. The car stops in 5s. Another driver going at 3km/ h⁻¹ in another car applies his brakes slowly and stops in 10s. On the same graph paper, plot the speed versus time graphs for the two cars. Which of the two cars travelled farther after the brakes were applied?

How will you separate a mixture of cooking oil (groundnut oil) and water?

Describe how the gravitational force between two objects depends on the distance between them.

1. Identify the figure.
2. Label W, X, Y and Z
3. What is chemical composition of material of the figure
4. What of the function of X?

Differentiate between axon and dendron.

Compute the difference in masses of one mole each of aluminium atoms and one mole of its ions (Mass of an electron is 9.1 × 10^-28 g). Which one is heavier?

Copper sulphate reacts with sodium hydroxide to form a blue precipitate of copper hydroxide and sodium sulphate. In an experiment, 15.95g of copper sulphate reacted with 8.0g of sodium hydroxide to form 9.75g of copper hydroxide and 14.2g of sodium sulphate. Which law of chemical combination is illustrated by this data? Give reason for your choice.

Four men lift a 250kg box to a height of 1m and hold it without raising or lowering it. (a) How much work is done by the men in lifting the box? (b) How much work do they do in just holding it? (c) Why do they get tired while holding it? (g = 10ms^-2)