A bird while flying takes a let turn, where does it get the centripetal force from?

From where do we get these different forms of energy?

The fastest possible of rotation of a planet is that for which the gravitational force on material at the equtor barely provides the centripetal force needed for the rotation. Show then that the corresponding shortest period of rotation is given by T=sqrt((3pi)/(Grho)) where rho is the density of the planet, assumed to be homogeneous. Evalute the rotation period assuming a density of 3.0 gm//cm^(2) , typical of many planets, satellites, and asteroids. No such object is found to be spinning with a period shorter than found by this analysis.

Assertion : If the earth stops rotating about its axis, the value of the weight of the body at equator will decrease. Reason : The centripetal force does not act on the body at the equator.

What are the main steps in aerobic respiration ? Where does it take place ?

A particle of mass m is moving in a horizontal circle of radius r, under a centripetal force equal to - (K//r^(2)) . Where K is constant. What is the total energy of the particle?

The magnetic force depends on v which depends on the inertial frame of reference. Does then the magnetic force differ from inertial frame to frame ? Is it reasonable that the net acceleration has a different value in different frames of reference ?

What are the main steps in aerobic respiration? Where does it take place?