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.
Answer:
Initial velocity, U = 28.73m/s
Explanation:
Given the following data;
Final velocity, V = 35m/s
Acceleration, a = 5m/s²
Distance, S = 40m
To find the initial velocity (U), we would use the third equation of motion.
V² = U² + 2aS
Where;
V represents the final velocity measured in meter per seconds.
U represents the initial velocity measured in meter per seconds.
a represents acceleration measured in meters per seconds square.
S represents the displacement measured in meters.
Substituting into the equation, we have;
35² = U + 2*5*40
1225 = U² + 400
U² = 1225 - 400
U² = 825
Taking the square root of both sides, we have;
Initial velocity, U = 28.73m/s
If the bag is motionless, then it's not accelerating up or down.
That fact right there tells you that the net vertical force on it
is zero. So the sum of any upward forces on it is exactly equal
to the downward gravitational force ... the bag's "weight".
If the bag is suspended from a single rope, then the tension
in the rope must be equal to the 100-N weight of the bag.
And if there are four ropes holding it up, then the sum of
the four tensions is 100N. If the ropes have been carefully
adjusted to share the load equally, then the tension is 25N
in each rope.
The process of changing from one phase of matter to another is a physical matter.
Answer:
D. infinitely extended in all directions
Explanation:
A semi infinite solid is infinitely extended in every direction. It has a single surface and can extend when heat is applied.
The body of a semi infinite solid is idealised, that is, when there is heat present, it expands in all directions to infinity. It can be used for a thick wall because its shape can be changed when subjected to different levels of heat near its surface.
It is also expands as heat is applied because its thickness is negligible.
This idealized body is used for earth, thick wall, steel piece of any shaped quenched rapidly etc indetermining variation of temperature near its surface & other surface being too far to have any impact on the region in short period of time since heat doesn’t have sufficient time to penetrate deep into body thus thickness can be neglected
