Can someone please help me with science. If you do not no the answer please do not answer it then.

Ahollow metal sphere has 6 cm and 11 cm inner and outer radii, respectively. the surface charge density on the inside surface is −100nc/m2. the surface charge density on the exterior surface is:

In positive numbers less than 1, the zeros between the decimal point and a non-zero number are blank significant

If an athlete runs once around a track, back to the starting line, her average velocity is zero. true or false?