Answer:
The magnitude of electron acceleration is

Explanation:
Given:
Distance from the wire to the field point
m
Speed of electron 
Current
A
For finding the acceleration,
First find the magnetic field due to wire,

Where 

T
The magnetic force exerted on the electron passing through straight wire,

N
From the newton's second law

Where
mass of electron
kg
So acceleration is given by,



Therefore, the magnitude of electron acceleration is

<span>7.21 ft/s^2
Since you're looking for average acceleration, you can simply divide the change in velocity by the time. To make the calculation more reasonable, first convert the speed of 173 mi/h into ft/sec by multiplying by 5280 to convert from mi/h to ft/h and then dividing by 3600 to convert from ft/h to ft/s.
173 * 5280 / 3600 = 253.7333 ft/s
Now divide the change in velocity by the time in seconds.
253.7333 ft/s / 35.2 s = 7.208333 ft/s^2
Rounding result to 3 significant figures gives 7.21 ft/s^2</span>
Hi,
My best answer would be Gravity. Is it a multiple choice question? Or is it an essay question.
I believe it’s nuclear energy.