Calculating Acceleration and Time in a Cathode Ray Tube | Physics Homework Help

[cbrowne]

Could someone please confirm my answer. Thanks

Homework Statement

An electron in a cathode ray tube of a TV set enters a region where it accelerates
uniformly from a speed of 3.5 × 104 m/s to a speed of 1.4 × 106 m/s in a distance
of 2.0 cm.
(a) What is the acceleration of the electron in this region?

(b) How long is the electron in the region where it accelerates?

Homework Equations

The Attempt at a Solution

Given the: initial velocity ---> u = 3.5 x 10^4 m/s
final velocity -----> v = 1.4 x 10^6 m/s

distanced traveled S= 2.0 cm --> 2x10^-2 m

Let acceleration be "a"

v2-u2= 2as

a= (v2-u2)/2s = 4.8969375 x 10^9 m/s

b) let time be "t"

v = u +at --> t = (v-u)/a = 0.278x 10^-3 s

 

[Kurdt]

I'd check your working again. Careful with units as well.

 

[Mentallic]

Your acceleration is 10,000x off the precise value
Thus, your time is off by the same magnitude.