# Micro-F Capacitor

Not what you're looking for?

Hi. Can someone please check these two answers? (a) seems very low and (b) seems very high to me.

A 0.22 micro-F capacitor is charged by a 1.5-V battery. After being charged, the capacitor is connected to a small electric motor. Assuming 100% efficiency, (a) to what height can the motor lift a 5.0-g mass? (b) What initial voltage must the capacitor have if it is to lift a 5.0-g mass through a height of 1.0 cm?

My solutions:

(a)

C = 0.22 micro-F = 0.22 x 10^-6 F

V = 1.5 V

m = 5.0 g = 5.0 x 10^-3 kg

h = ?

Q = CV = 3.3 x 10^-7

U = (1/2)QV = 2.5 x 10^-7 J

ANSWER: U = mgy , y = U/mg = 5.1 x 10^-6 m

(b)

V = ?

m = 5.0 x 10^-3 kg

C = 0.22 x 10^-6

h = 1 cm = 0.01 m

U = mgy = 4.9 x 10^-4 J

ANSWER: U = (1/2)QV , V = U /(1/2)Q = 2970 V

Thank you.

##### Purchase this Solution

##### Solution Summary

The expert examines micro-F capacitor voltages. The solution includes a 150-200 word explanation.

##### Solution Preview

Your work for (a) is certainly correct.

Your work for (b) is certainly correct.

Whoever wrote the question certainly didn't use realistic examples. Although (a) is a bit realistic if you think of MEMS (Micro-electro-mechanical systems). Moving a micro-mechanical beam 5.1um ...

##### Purchase this Solution

##### Free BrainMass Quizzes

##### Basic Physics

This quiz will test your knowledge about basic Physics.

##### Intro to the Physics Waves

Some short-answer questions involving the basic vocabulary of string, sound, and water waves.

##### The Moon

Test your knowledge of moon phases and movement.

##### Introduction to Nanotechnology/Nanomaterials

This quiz is for any area of science. Test yourself to see what knowledge of nanotechnology you have. This content will also make you familiar with basic concepts of nanotechnology.

##### Classical Mechanics

This quiz is designed to test and improve your knowledge on Classical Mechanics.