Answer:
1 is c 2 is a and 3 is b hope that helped!
Firstly they have a acceleration downwards due the force downwards due they gravitational field acting on it's mass.
as it falls it gains speed, and as it gains speed the air Resistance which is a upward force actin on the drop increases, eventually the rain drop's upward and downward forces are balanced and hence there is no RESULTANT force therefore no acceleration, so the drops falls in constant speed (terminal verlocity is a better term)
Are you wondering that why is the raindrop still moving given that the forces are balanced? If so according to Newton's 1st law an object will keep moving or Remain at rest until a RESULTANT force acts on it.
Answer: Object B
Explanation: Acceleration is directly proportional to force and inversely proportional to mass. It implies that more massive objects accelerates at a slower rate.
To solve this problem we will apply the concepts related to wavelength as the rate of change of the speed of the wave over the frequency. Mathematically this is

Here,
v = Wave velocity
f = Frequency,
Replacing with our values we have that,

\lambda = 0.68m
The distance to move one speaker is half this

Therefore the minimum distance will be 0.34m
Answer:
3 years
Explanation:
Find the circumference of each orbit in AU.
2xπx1=6.283185307
2xπx3=18.84955592
Divide them.
18.84955592/6.283185307=3
3 years