The escape velocity of a body depends upon mass as

Which of the following is more close to a black body?

The kinetic energy needed to project a body of mass $$m$$ from the earth surface (radius $$R$$) to infinity is

A solid sphere, a hollow sphere and a ring are released from top of an inclined plane (frictionless) so that they slide down the plane. Then maximum acceleration down the plane is for (no rolling)