The escape speed of a projectile on the earth's surface is 11.2 km s^(-1). A body is projected out with thrice this speed. What is the speed of the body far away from the earth? Ignore the presence of the sun and other planets.

The escape speed of a projectile on the earth's surface is 11.2 km s^(

1.	The escape speed of a projectile on the earth's surface is 11.2 km s^(-1). A body is projected out with thrice this speed. What is the speed of the body far away from the earth? Ignore the presence of the sun and other planets.
Answer» Solution :`V_e=11.2 kms^(-1)`, velocity of projection `=v=3v_e` Let m be the mass of projectile and `v_(0)` the velocity after it escape gravitational pull. By 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(9v_(e )^(2)-v_(e )^(2))= sqrt(gv_(e )^(2))` `=22.4sqrt(2)` `=31.68 kms^(-1)`.