A.The density of milk decreases when cream is taken out of milk
B.A cyclist should move along a zig-zag path while ascending a steep hill
C.The linear velocity of bodies near the earth’s equator (due to rotation of earth) is more than the velocities of particles at the pole
D.The potential energy of a particle has the form Ep = k2x. The force acting on the particle is constant (k is a constant)