Gravitation — Maharashtra (SSC) Class 10 Science Solutions (Free)

Gravitation is the force of attraction between any two objects in the universe. Gravitational force is the attractive force that exists between all masses. It is always present and acts along the line joining the centers of the two objects. The magnitude depends on the masses and inverse square of the distance between them.

Acceleration due to gravity (g) is the acceleration produced when a body falls freely under the influence of gravitational force. g = 9.8 m/s2 at earth's surface. g varies with latitude because Earth is oblate (flattened at poles). At equator, radius is maximum, so g is minimum (9.78 m/s2). At poles, radius is minimum, so g is maximum (9.83 m/s2).

Step 1: Use h = (1/2)gt2, where h = 80 m, g = 10 m/s2 Step 2: 80 = (1/2) x 10 x t2 Step 3: 80 = 5t2 Step 4: t2 = 16 Step 5: t = 4 seconds Answer: Time taken is 4 seconds.

Escape velocity is the minimum velocity required by an object to escape from the gravitational pull of a celestial body without further propulsion. For Earth, escape velocity = 11.2 km/s = 11200 m/s. It is independent of the mass of the escaping object but depends on the mass and radius of the celestial body.

Step 1: Mass on Earth = W/g = 100/10 = 10 kg Step 2: Mass remains constant everywhere = 10 kg Step 3: Weight on Moon = m x g(moon) = 10 x 1.6 = 16 N Answer: Weight on Moon is 16 N. Note: Weight changes, but mass is constant.