Acar speeds up from 13 m/s to 23 m/s in 30 seconds. what is the acceleration of the car?

Well, v = u + a×t is the equation.

v: final velocity, which is 23 m/s in this equation.
u: initialo velocity = 13 m/s 
a: acceleration = ? 
t: time = 30s 

Your equation would be...

23 = 13 + a×30 
a = (23 - 13) / 30 
a = 1 / 3 
a = 0.333 m/s

Electoral current force mechanical advantage if the wheel and axle is 2 n and the output force is 20 n