In a physics experiment, Stan has two lab carts. The blue lab cart has a mass of 0.5 kg and the red cart has a mass of 2.0 kg. In one experiment, Stan set the two carts at rest
on the track. He pushes in the plunger between them and releases it. He uses a
stopwatch to determine that after he releases the plunger, the red cart rolls to the right
at a velocity of 4 m/s.
Determine the velocity of the blue cart after the explosion.

Search coils and credit cards. one practical way to measure magnetic field strength uses a small, closely wound coil called a search coil. the coil is initially held with its plane perpendicular to a magnetic field. the coil is then either quickly rotated a quarter-turn about a diameter or quickly pulled out of the field. (a) derive the equation relating the total charge q that flows through a search coil to the magnetic-field magnitude b. the search coil has n turns, each with area a, and the flux through the coil is decreased from its initial maximum value to zero in a time ∆t. the resistance of the coil is r, and the total charge is q = i∆t, where i is the average current induced by the change in flux. (b) in a credit card reader, the magnetic strip on the back of a credit card is rapidly “swiped” past a coil within the reader. explain, using the same ideas that underlie the operation of a search coil, how the reader can decode the information stored in the pattern of magnetization on the strip. (c) is it necessary that the credit card be “swiped” through the reader at exactly the right speed? why or why not?

2. circled insects have mutations, or changes to their dna. how many of the offspring insects in this generation have mutations?

Acircular ring of charge with radius b has total charge q uniformly distributed around it. what is the magnitude of the electric field at the center of the ring? 0 keq/b2 keq2/b2 keq2/b none of these answers