Just registered on these forums because I need some physics help! Teacher doesn't explain things adequetly(sp?) So how do you solve these problems in general terms? "A 4:24 kg mass attached to a light string rotates on a horizontal, frictionless table. The radius of the circle is 0:548 m, and the string can support a mass of 16:2 kg before breaking. The acceleration of gravity is 9:8 m=s2 : What maximum speed can the mass have before the string breaks? Answer in units of m=s." "If the gravitational force between the elec- tron (of mass 9:11 £ 10¡31 kg) and the proton (of mass 1:67 £ 10¡27 kg) in a hydrogen atom is 5 £ 10¡48 N, how far apart are the two par- ticles? The universal gravitational constant is 6:673 £ 10¡11 N ¢ m2=kg2. Answer in units of m."