Question

A proton initially moves left to right long the x‑axis at a speed of 2 ´ 103 m/s. It moves into an electric field, which points in the negative x direction, and travels a distance of 0.2 m before coming to rest. What acceleration magnitude does the proton experience?

a. 6.67 ´ 103 m/s2
b. 1.0 ´ 107 m/s2
c. 9.33 ´ 109 m/s2
d. 2.67 ´ 1011m/s2

Please show all calculations THANKS!

Answer 1

Vf^2=Vi^2+2ad

you know Vf=0, Vi=2E3m/s, d=.2m

solve for a

Answer 2

why is the 'a'---the variable i'm solving for positive though? I got a (-) 'a' when I followed your steps....thanks for the help though!

Answer 3

Of course, a is negative, it is deaccelerating in the +x direction, or accelerating in the -x direction.