Thallium- 208 has a half life of 3 minutes How much of a 60.0 sample of thallium -208 will be left after 4 half lives

When the force acting on an object points at least partially in the direction of the motion the work done is considered to be negative

If steel is more dense that lake water, why can a boat float

Atotal charge of –6.50 µc is uniformly distributed within a sphere that has a radius of 0.150 m. what is the magnitude and direction of the electric field at 0.300 m from the surface of the sphere? a) 2.89 × 105 n/c, radially inward b) 6.49 × 105 n/c, radially outward c) 4.69 × 105 n/c, radially inward d) 9.38 × 105 n/c, radially outward e) 1.30 × 106 n/c, radially inward