In his famous experiment with electrons, j. j. thompson measured the "charge-to-mass-ratio" r = en, where e is the electron's charge and m is its mass. a modern classroom version of this experiment finds the ratio r by accelerating electrons through a voltage vand then bending them in a magnetic field. the ratio r=e/m is given by the formula: 125 d2v in this experiment, ilo is the permeability constant of a vacuum (equal to 4π x 10" na exactly) and n is the number of turns in the coil that produces the magnetic field. d is the diameter of the field coils, v is the voltage that accelerates the electrons, d is the diameter of the electro curved path, and / is the current in the field coils. a student makes the following measurements: n= 72 (exactly) d-661 ± 2 mm v= 45.0 ± 0.2 volts d=91.4±0.5 mm |= 2.48 ± 0.04 amps (a) find the student's answer for the charge-to-mass ratio of the electron, with its uncertainty. (assume all uncertainties are independent and random.) (b) how well does this answer agree with the accepted value r= 1.759x10" c/kg?

For problems 1-3, consider a simple dc brush motor with a permanent magnet stator. with an an consider a simple dc brush motor with a permanent magnet ae supply voltage of 100 v, the no-load speed of the motor is 1000 rpm. this motor can provide a torque of 1.9 n-m at 800 rpm drawing a current of 2 a current are both zero at no load.) 1. with an armature supply voltage of 100 v, the motor is operated at 900 rpm. what is the motor torque? what is the mechanical power delivered by the motor? what is the current draw? what is the electrical power input? what is the energy efficiency of the motor? with an armature supply voltage of 100 v, the motor is operated at 1100 rpm (where it acts as a generator). what torque input is required? what mechanical power is required what current is generated? what is the electrical power generated? what is the energy efficiency of the motor acting as a generator? 2. with an armature supply voltage raised to 120 v, the motor is operated at 1000 rpm. what is the no-load speed? what is the motor torque? what is the mechanical power delivered by the motor? what is the current draw? what is the electrical power input what is the energy efficiency of the motor? 3.

For the car in the picture ,in which direction is the normal force? -into the screen -down -out of the screen -up

Aswimming pool whose volume is 10 comma 000 gal contains water that is 0.01% chlorine. starting at tequals0, city water containing 0.003% chlorine is pumped into the pool at a rate of 5 gal/min. the pool water flows out at the same rate. what is the percentage of chlorine in the pool after 1 hour? when will the pool water be 0.006% chlorine?