Explanation:
Let the speeds of father and son are
. The kinetic energies of father and son are
. The mass of father and son are 
(a) According to given conditions, 
And 
Kinetic energy of father is given by :
.............(1)
Kinetic energy of son is given by :
...........(2)
From equation (1), (2) we get :
..............(3)
If the speed of father is speed up by 1.5 m/s, so the ratio of kinetic energies is given by :


Using equation (3) in above equation, we get :

(b) Put the value of
in equation (3) as :

Hence, this is the required solution.
Inside the bar magnet, the magnetic field points from north to south. Statement A is correct.
Magnetic Field:
It is defined as a vector field or the influence of the magnet on the electric current, charges and ferromagnetic substance.
The strength of magnetic field is depends up on the numbers of magnetic field lines per unit area.
- Magnetic field lines emerge from the North pole and end in the South pole of a bar magnet.
- Inside the magnet are also present inside the bar magnet and never intersect at any point.
Therefore, inside the bar magnet, the magnetic field points from north to south.
To know more about Magnetic Field:
brainly.com/question/19542022
Answer:
Plato, Aristotle developed it further and used for 1400 years till Copernicus.
Explanation:
the answer is 1a as rearrange gives I = v divided by r