1) 15 / 12 = 1.25 ratio
2) to increase acceleration 1.25 times (with same F, or same engine) you have to lower mass 1.25 times
3) 1515/1.25 = 1212 kg
choose A
Answer:
a). 87.5 mA or
A
b). 1.78 
Explanation:

n the number of free electrons is 28 in text reference and if they don't give q is take as the charge of electron.
a).
A
b).


No not all, because not all electrical field attract and repel
To solve this problem it is necessary to apply the equation related to the Gravitational Force, the equation describes that

Where,
G = Gravitational Universal Constant
M = Mass of Earth (or Bigger star)
m = Mass of Object (or smallest star)
r = Radius
From the statement we know that once the impact is made, the golf ball is subjected to the forces that are exerted in nature. Since the air resistance, which would represent the drag force, is ignored. Only the forces related to gravity remain.
The gravitational force carries 'pushes' or 'attracts' the body towards the earth, while the speed decreases as it reaches its maximum height.
When the ball has reached its maximum height only the force of gravity begins to act on it, generating the attraction to the earth in parabolic motion.
Therefore the correct answer is B.