The escape velocity of a projectile on the surface of earth is 11.2 kms^(-1) . If a body is projected out with thrice this speed, find the speed of the body far away from the earth. Ignore the presence of other planets and sun.

The escape velocity of a projectile on the surface of earth is 11.2 km

1.	The escape velocity of a projectile on the surface of earth is 11.2 kms^(-1) . If a body is projected out with thrice this speed, find the speed of the body far away from the earth. Ignore the presence of other planets and sun.
Answer» Solution :Here, `v_e = 11.2 kms^(-1) ` , velocity of projection of the BODY `v = 3v_e`. Let m be the mass of the PROJECTILE and `V_0` . be the velocity of the projectile when FAR away from the earth (i.e. out of gravitationalfield of earth). Then from the law of conservation of energy. ` 1/2 mv_0^2 = 1/2 mv^2-1/2 mv_e^2` `v_0 = sqrt(v^2 -v_e^2) = sqrt((3v_e)^2 - v_e^2)` ` = sqrt8 XX 11.2 = 31.68 kms^(-1)`