Find the net charge on the shell

[dwx1]

Can anyone help me with this problem? I've been working on it for hours and can't get anywhere with it, I just have no idea how to do it at this point.

A cylindrical shell of radius 7.00 cm and length 240 cm has its charge uniformly distributed on its curved surface. The magnitude of the electric field at a point 19.0 cm radially outward from its axis (mesaured from the midpoint of the shell) is 36.0 kN/C. Find (a) the net charge on the shell and (b) the electric field at a point 4.00 cm from the axis, measured radially outward from the midpoint of the shell.

Anyone?
Thanks so much.

 

[Galileo]

As the title indicates, use Gauss' Law. The Gaussian surface should be obvious to choose and easy to evaluate because of symmetry.

Show us what you've got so far.