an object of mass 800 gram hangs on a spring calculate the force exerted by the object of acceleration due to gravity is 10m/s square​

What is the weight of a feather (mass = 0.0001 kg) that floats through earth's and the moon's atmospheres?

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 does si stand for,when referring to a system of measurement