. How much force would it take to push another, larger friend who has a mass of 70 kg to accelerate at the same rate of 4 m/s2?

Two steel balls, each of mass m, are welded to a light rod of length l and negligible mass and are initially at rest on a smooth horizontal surface. a horizontal force of magnitude f is suddenly applied to the rod as shown. determine (a) the instantaneous acceleration a of the mass center g and (b) the corresponding rate at which the angular velocity of the assembly about g is changing with time.

What is an example of static friction

What happens when the number of protons in an atom changes