answer in millimeters

A macroscopic (or macro) lens for a camera is usually a converging lens of normal focal length built into a lens barrel that can be adjusted to provide the additional lens-to-film distance needed when focusing at very close range. Suppose that a macro lens (f = 53.0 mm) has a maximum lens-to-film distance of 271 mm. How close can the object be located in front of the lens?

What is the height (including sign) of her image on the film

A camera is supplied with two interchangeable lenses, whose focal lengths are 35.0 and 150.0 mm. A woman whose height is 1.80 m stands 7.00 m in front of the camera. What is the height (including sign) of her image on the film, as produced by a 35.0-mm and 150.0-mm lens?

Resistors1

1. A 4.0(the symbol looks like a set of headphones, sorry thats the best I can do to describe it) resistor, an 8.0(headphones symbol) resistor, and a 12.0(headphones symbol) resistor are connected in a series with a 24.0 V battery. A. Calculate the equivalent resistance. B. Calculate the current in the curcuit. C. What is the current in each resistor? Please include the answer, formulas used and work done. Thank you so much!

Resistors

1. A series combination of two resistors, 7.25(the symbol looks like a set of headphones, sorry thats the best I can do to describe it) and 4.03(headphones symbol), is connected to a 9.00 V battery. A. Calculate the equivalent resistance of the curcuit and the current. B. What is the potential difference across each resistor? Please include the answer, formulas used and work done. Thank you so much!

Relativity

In the old west, a marshal riding on a train traveling 50m/s sees a duel between two men standing on the earth 50m apart parallel to the train. The marshal's instruments indicate that in his reference frame the two men fired simultaneously. (a) Which of the two, the first one the train passes (guy A) or the second (guy B), should be arrested for firing the first shot? (b) How much earlier did he fire? (c)Who was struck first? (d) Who is struck first according to the marshal and explain why? I keep trying to work the problem using the Lorentz Transformation.