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:
Explanation:
The attached figure shows the whole description. Considering the applied force is 100 N.
The acceleration of both blocks A and B, 
Firstly calculating the mass m using the second law of motion as :
F = ma
m is the mass
m = 125 kg
It suddenly encounters a surface that supplies 25.0 N a friction, F' = 25 N
So, the new acceleration of the block is 
. Hence, this is the required solution.
Answer:
Explanation:
The energy of Mass-Spring System the sum of the potential energy of the block plus the kinetic energy of the block:
Where:
There are two cases, the first case is when the spring is compressed to its maximum value, in this case the value of the kinetic energy is zero, since there is no speed, so:
The second case is when the block passes through its equilibrium position, in this case the elastic potential energy is zero since 
, so:
Now, let's find the energy of the system when the block is replaced by one whose mass is twice the mass of the original block using the previous data:
Where in this case:
Therefore:
The distance - time graph of the humming bird is missing, so i have attached it.
Answer:
Instantaneous velocity = 0.5 m/s
Explanation:
From the attached graph, at time t = 1 s, the corresponding distance is 0.5 m.
Instantaneous velocity is the velocity at that point.
Thus;
Instantaneous velocity = 0.5/1
Instantaneous velocity = 0.5 m/s
1) Ecology
2) Food Web
3) Trophic Level
4) Producer
5) Autotroph
6) Consumer
7) Heterotroph
8) Decomposer
Hope tHis Helps ._.
