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
QUESTION:-A beam of white light shines onto a sheet of white paper. An identical beam of light shines onto a mirror. The light is scattered from the paper and reflected from the mirror.
Describe how scattering by paper and reflection by a mirror are different from each other.
ANSWER: Scattering sends or reflects light from each point on the object in all directions, whereas reflection sends light from each point on the object in one direction only (or to one point)
Answer:
Rate of change of water will be -6 gallon/minute
Explanation:
We have given water in the tank as the function of time as

We have to find the rate of change of water in the tank at t = 3 minute
For rate of change we have to differentiate both side
So 
At t = 3 minute

Answer:
F = - 59.375 N
Explanation:
GIVEN DATA:
Initial velocity = 11 m/s
final velocity = 1.5 m/s
let force be F
work done = mass* F = 4*F
we know that
Change in kinetic energy = work done
kinetic energy = 
kinetic energy =
= -237.5 kg m/s2
-237.5 = 4*F
F = - 59.375 N