Which protects a cell and forms it's boundary

An external resistor with resistance R is connected to a battery that has an emf E and an internal resistance r. Let P be the electrical power output of the source. By conservation of energy, P is equal to the power consumed by R.

If Earths gravitational pull got 3 times stronger ... What would happen to our weight?

A constant magnetic field can be used to produce an electric current. True or False?

Ilya and Anya each can run at a speed of 7.70 mph and walk at a speed of 4.00 mph. They set off together on a route of length 5.00 miles.

What waves are passing through your house or classroom daily? (Tell what device is using them, think of the movie Tour of the EM spectrum.)

Which statement is true about the atom? A: it contains positive electrons, uncharged protons and negative protons. B: it contains uncharged neutrons, positive electrons and negative protons.

Steel objects can become temporary magnets because they are mainly composed of which element?

How long does it takes the sun to rotate the earth?

Which explains how winds move?

Why is it important to develop alternative energy sources