Answer:
medium
Examples:
A medium is a thing that the sound wave would travel through, like sound waves traveling through air. A mechanical wave cannot travel without a medium, like if the wave were trying to travel through a vacuum.
Answer:
Increase in total energy will be equal to the increase in the internal energy i.e
Joules
Explanation:
Given
Weight of sledge hammer
kilogram
Speed of sledge hammer
meter per second
Kinetic energy is equal to half the product of mass and velocity square

Substituting the value of mass and velocity, we get -

It is given that one fourth of the energy is converted into internal energy
One fourth of kinetic energy is equal to

Increase in total energy will be equal to the increase in the internal energy i.e
Joules
Answer:

Explanation:
= Rate at which the distance between A and starting point of B is changing = -20 km/h
= Rate at which the distance of B is changing = 15 km/h
= Rate at which the distance between A and B is changing
Time after which the rate at which the distance between A and B is changing is 4 hours
Distance covered by A in 4 hours = 
a = Distance remaining to the start point of B = 
b = Distance covered by B in 4 hours = 
Distance between A and B after 4 hours


Differentiating with respect to time we get

The rate at which the distance between the ships is changing at 4 PM is
.
It is in its ground state when its orbital electron is at its lowest energy amount.
- Unlike charges attract .
- like charges repel .
There are two types of charges
Namely :
On loosing electrons , a neutral body acquires positive charge .
On gaining electrons , a neutral body acquires negative charge .
The amount of charge present in a body , either positive or negative , is expressed in terms of an integral number of charge of an electron , which is considered the elementary entity of an electric charge .