Answer:
These forces are all equal and cancel each other out. Gravity pushes downward on the ice cream. This can also be called the weight of the ice cream. Buoyant force pushes the ice cream upward
Answer:
Constructive interference
Explanation:
Here, the medium is same, same wavelength, same frequency, same amplitude and same direction of propagation.
Let the intensity of waves be I which is same for both
The formula for the net intensity is

where, Ф be the phase difference
So, 
Here, IR is maximum so the interference is constructive in nature.
Well, one AU is 149,597,870 km. So, we would basically have to divide 4.5 billion km by 149,597,870, right?
4,500,000,000/149,597,870=30.080642 AU.
So, the correct answer would be 30 AU. Hoped this helped!
It starts or speeds up.
Some substances need certain amount of energy in order to react with each other.
You may know linear momentum is given by
P= mass.velocity.
Initially car is moving with some velocity so you know initial momentum of the car. Finally it comes to rest i.e final momentum of the car is 0. According to Newton's second law : Force = change in momentum /time. Applying this you'll get answer as 642840N. Hope it helped you. Revert back to me if you have any questions. Please check out the calculation it might be wrong!