A spring scale reads 5 N as it pulls a 10 kg block across a rough surface. If the block is moving at a constant speed, what is the force of friction? A) 5 N
B) 0 N
C) 50 N
D) 15 N

The magnetic field inside a superconducting solenoid is 4.50 t. the solenoid has an inner diameter of 6.20 cm and a length of 26.0 cm. determine (a) the magnetic energy density in the field and (b) the energy stored in the magnetic field within the solenoid.

Clothes dryer uses about 7 amps of current from a 240 volt line. how much power does it use?

Which of these is constant for all types of electromagnetic radiation in a vacuum? select one: a. wavelength b. frequency c. photon energy d. amplitude e. velocity