Answer:
Force is 57.69 N to the opposite direction of motion of dolphin.
Explanation:
We have force is the product of mass and acceleration.
That is
Force = Mass x Acceleration
F = ma
Mass of dolphin, m = 30 kg
We have equation of motion, v = u + at
Final velocity, v = 7 m/s
Initial velocity, u = 12 m/s
Time, t = 2.60 s
Substituting
7 = 12 + a x 2.6
a = -1.92 m/s²
Force, F = 30 x -1.92 = -57.69 N
So the force is 57.69 N to the opposite direction of motion of dolphin.
The total momentum of the system has to be conserved to satisfy the principle of conservation of momentum. Before the ball hits the bottle, the momentum of the system is 0.4 x 18 = 7.2 kg m/s
The momentum of the bottle after being hit is 0.2 x 25 = 5 kg m/s
So the momentum of the ball now is 7.2 - 5 = 2.2 kg m/s
Hence its velocity is 2.2/0.4 = 5.5 m/s
This process shows alpha decay so X represents an alpha particle. The characteristic of alpha decay is that the mass number stays constant while the proton number increases.
Harmonics, Loop and Harmonic number
Hope this helps :)
Answer:
With the exception of natural gas fossil fuel energies have seen an overall decrease since year 2000.
Explanation:
Just observe the graph
The Fossil fuels include-Petroleum ,coal and natural gases.
- The graph of these goes fastly up during 20th century but ,then it stabled at the peak then has not shown any solid increase .
- Observe other energy sources graph ,nuclear energy etc have shown quite speedy increase .
Option C is correct
