Gravitation — Science STD 9 — Question

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?

A man throws a ball weighing 500g vertically upwards with a speed of 10m/s.

1. What will be its initial momentum?
2. What would be its momentum at the highest point of its flight?

A force of 50N acts on a body and moves it a distance of 4m on a horizontal surface. Calculate the work done if the direction of force is at an angle of 60° to the horizontal surface.

State one property in which a solution of sugar in water resembles a mixture of sugar and sand, and one property in which it differs from it.

What is urban waste? What does it include ?

Atom A has a mass number 209 and atomic number 82.
Atom B has a mass number 209 and atomic number 83.

1. How many protons atom A has?
2. How many protons atom B has?
3. Are atoms A and B isotopes of the same element?

How is the impurity of iron present in several substances removed in industries?

What do you understand by the term ‘acceleration due to gravity of earth'?

Classify the following as physical or chemical changes:

1. Formation of curd from milk.
2. Condensation of steam.
3. Growth of a plant.
4. Breaking of a glass tumbler.