Science

In Today's class I learnt Acceleration due to gravity and Factors affecting acceleration due to gravity.

Acceleration due to gravity

>>Our earth attracts all the objects toward its centre by a force called gravity.

>>force acting on a mass of a body is known as its weight.

>>Weight varies from place to place with the force of gravity. The force of gravity is more on the places closer to centre of the Earth. The force of gravity produces acceleration when objects fall under its influence. This is called acceleration due to gravity.

>> It is denoted by letter ‘g’. The value of ‘g’ of the Earth is 9.8 ms-2 (approximately 10 ms-2). This means that every second an object is in free fall, gravity will cause the velocity of the object to increase 9.8 m/s. The objects falling from greater height reach the ground with higher velocity than those falling from lesser height. The difference in velocities of the falling objects is due to the force of gravity.

>>The acceleration due to gravity of other planets and the Moon is different. Larger the mass of planet, greater is the acceleration due to gravity.

Factors affecting acceleration due to gravity

1. Latitude – The Earth is slightly flattened at poles, therefore, object at the poles are closer to centre of the Earth. Closer the object to the poles, more is the acceleration due to gravity; closer the object to the equator, lesser is the acceleration due to gravity.

2. Altitude – With the increase in altitude, the Figure 9.3. Centre of the Earth. acceleration due to gravity decreases and vice versa. The red arrow in Figure 9.3. shows the direction of increase in altitude. As you go away from the surface of the Earth, the value of ‘g’ decreases.