Improvement in Food Resources — Science STD 9 — Question

Which part of neuron receives and transmits impulses?

Mitali weights 750N on the earth. On the planet mars, the force of gravity is 38% of that of the earth. How much will Mitali weight on the mars?

Explain why do spinach look green, papaya yellow and edible part of water melon red?

If a fresh egg is put into a beaker filled with water, it sinks. On dissolving a lot of salt in the water, the egg begins to rise and then floats. Why?

Would you cool a bucket of water more quickly by placing it on ice or by placing ice in it? Give reasons for your answer.

The mass number of an element is 23 and it contains 11 electrons. What is the number of protons and neutrons in it? What is the atomic number of the element?

Describe a method of separate a mixture of common salt and sand.

A moving bicycle comes to rest after sometime if we stop pedalling it. But Newton’s first law of motion says that a moving body should continue to move for ever, unless some external force acts on it. How do you explain the bicycle case?

A car is moving on a level road. If the driver turns off the engine of the car, the car’s speed decreases gradually and ultimately it comes to a stop. A student says that two forces act on the car which bring it to a stop. What could these forces be? Which of these two forces contributes more to slow down and stop the car?