Physics Answers

A certain gasoline weighs 46.5 lb/ft3 . What are its mass density, specific volume and specific gravity?

The specific gravity of ethyl alcohol is 0.79. Calculate its specific weight (in both pounds per cubic foot and kilonewtons per cubic meter) and mass density (in both slugs per cubic foot and kilograms per cubic meter). 

A 3.5-kg computer printer is pushed at a constant velocity across a desk with a horizontal force. The coefficient of kinetic friction between the printer and the desk is 0.36.

a) Calculate the magnitude of the normal force acting on the printer.

b) Calculate the magnitude of the kinetic friction acting on the printer.

It takes 36 sec for 0.01 moles of He to effuse through a pinhole in an effusion

apparatus. It takes 72 sec for 0.01 moles of another gas to effuse through the

same system. What is the molecular weight of the unknown gas?

A triode passes a plate current of 5mA at plate voltage 150V and grid voltage of -2V. If the grid voltage is changed to -35V, the plate current drops to 3.2mA but can be restored to 5mA by increasing plate voltage to 195V. Calculate

(1) mutual conductance

(2) a.c. plate resistance

(3) amplification factor

An object is placed 20cm from a converging lens. If the real image formed is 80.0cm from the object, the focal length of the lens is

An object is placed 20cm from a converging lens if the real image formed is 80.0cm from the object, the focal length of the lens is ?

A charge of 12 uC when placed in electric field experiences a force of 648 N. What is the magnitude of the electric field strength.

Two charges of +8.0mC and -6.0 mC attract each other with a force of 3.0x103 N in a vacuum. What is the distance between the charges.

Find the electrostatic force between charges of +2.0 C and +5.0 C separated by a distance of 75m in a vacuum.