Answer:
The velocity of the freight car decreases.
Explanation:
This question is answered by the conservation of momentum principle.
When the freight car is moving at a certain speed, it has a constant momentum.
We will call this M1.
The equation for M1 will be:
M1 = Mass * Speed
Now when the coal is dumped into the freight car, the Mass increases.
Since conservation of momentum states that the momentum will remain the same. We have:
M1 = (Mass of freight + Mass of coal) * Speed
Since M1 is constant, if the mass increases, the speed had to decrease to keep the equation true.
Answer:
the initial velocity of the ball is 104.67 m/s.
Explanation:
Given;
angle of projection, θ = 60⁰
time of flight, T = 18.5 s
let the initial velocity of the ball, = u
The time of flight is given as;

Therefore, the initial velocity of the ball is 104.67 m/s.
Answer: The first crane has greater power
Explanation:
Answer:
7
Explanation
There are currently seven complete periods in the periodic table, comprising the 118 known elements. Any new elements will be placed into an eighth period; see extended periodic table.