Answer:
a) m=20000Kg
b) v=0.214m/s
Explanation:
We will separate the problem in 3 parts, part A when there were no coals on the car, part B when there is 1 coal on the car and part C when there are 2 coals on the car. Inertia is the mass in this case.
For each part, and since the coals are thrown vertically, the horizontal linear momentum p=mv must be conserved, that is, 
, were each velocity refers to the one of the car (with the eventual coals on it) for each part, and each mass the mass of the car (with the eventual coals on it) also for each part. We will write the mass of the hopper car as 
, and the mass of the first and second coals as 
and 
respectively
We start with the transition between parts A and B, so we have:
Which means
And since we want the mass of the first coal thrown () we do:
Substituting values we obtain
For the transition between parts B and C, we can write:
Which means
Since we want the new final speed of the car (
) we do:
Substituting values we obtain
Answer:
The 10 kg rock has more inertia than the other two rocks.
Explanation
Give me some answer choices and i will be happy to help
Answer:
(a) A+B = 2i-3j
(B) A-B = 4i + j
Explanation:
We have given two vectors A = 3i-j and B = -1-2j
We have to find the two vectors that is A+B and A-B
(A) In first art we have calculate A+B for this we have to add simply vector A and v ector B
So A+B = 3i-j-i-2j = 2i-3j
(B) In this part we have to find A-B for this we have to simply subtract B from A so A-B = 3i-j-(-i-2j) =3i-j+i+2j =4i+j
He was the first to improve the telescope i believe
