Centripetal Force required to hold electron

[nobrainer612]

Homework Statement

An electron ( m = 9.11 * 10^-31 kg) moves in a circular orbit of radius 0.4 * 10^-10 m with an angular velocity of 2* 10^16 rad/s. Find the centripetal force required to hold the electron.

Homework Equations

This is one question from the chapter " Forces Due to Magnetic Fields and Electric Fields.

The Attempt at a Solution

When I look at this question, I felt kind of weird. Because it is asking me the centripetal force required to hold the electron. But this chapter is about the force done by magnetic fields and electric field on a particle. But the question gave me all values to calculate the centripetal force, and I feel like nothing related to this chapter.

Even though I am confused, I tried to calculate it.

angular velocity: w , v = velocity , r = radius, Fc = centripetal force, m = mass of electron

w = v / r
v = w * r
= ( 2 * 10^16) * (0.4 * 10^-10)
= 800000 m/s

Fc = (m* v^2)/r
= ((9.11 * 10^-31) * (800000)^2 ) / (0.4*10^-10)
= 1.4576 * 10^-8


Please guide me to the correct way , or am I correct?
Thank you

 

[tiny-tim]

hi nobrainer612!

yes that's fine

(though 3 significant figures would be enough)

but learn the quicker alternative formula for centripetal acceleration …

ω²r ​