PLEASE HELP! This questions is from thehttp://www.collegeboard.com/prod_download

Question

PLEASE HELP!
This questions is from thehttp://www.collegeboard.com/prod_downloads/ap/students/physics/b_physics_b_frq_03.pdfwebsite, which is a 2003 AP Physics B free Response questions (formB) practice test, however I cannot find the answer anywhere. I need to know the steps as well as the final answer.:
A student is asked to design a circuit to supply an electric motorwith 1.0 mA of current 3.0 V potential difference.

a) Determine the electric energy to be supplied to the motorin 60 s.

b) Operating the motor can lift a 0.012 kg mass a distance of1.0 m in 60 s at constant velocity. Determine the efficiencyof the motor.

c) determine the power to be supplied to the motor.

To operate the motor, the student has available only a 9.0 Vbattery to use as the power source and the following fiveresistors: 1000, 4000, 4000,5000,10,000.

d) complete a schematic diagram of a circuit that shows how one ormore of these resistors can be connected to the battery and motorso that 1.0 mA of current and 3.0 V or potential difference aresupplied to the motor. Be sure to label each resistor in thecircuit with the correct value of its resistance.

PLEASE OFFER ANY HELP THAT YOU CAN! THANK YOU FOR YOUR TIME!!!

Explanation / Answer

P=U*I W=P*t=U*I*t=0,18(J) ------------------------ the work to bring the mass up is. 0,012*1*9,8=0,118(J). effiecent H=0,118/0,18=65% ---------------------- power to be supplied P=U*I=3e-3(W) ----------------------- motor resistance is R=3/1e-3=3000ohm. so for the current to be 1e-3A. the total resistance. is9/1e-3=9000ohm. so it is the motor seried with 1000 ohm and 5000ohm resistor

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.