Answer:
is the mass of librarian.
Explanation:
Given:
N<u>ow using the principle of elastic collision:</u>
Net momentum of the system is zero.
is the mass of librarian.
Answer:
The wife have to sit at 0.46 L from the middle point of the seesaw.
Explanation:
We need to make a sketch of the seesaw and the loads acting over it.
And by the studying of the Newton's law we can find the equation useful to find the distance of the mother sitting on the seesaw with respect to the center ot the pivot point.
A logical intuition will give us the idea that the mother will be on the side of her son to make the balance.
The maximum momentum with respect to the pivot point (0) will be:
Where L/2 is the half of the distance of the seesaw
Therefore the other loads ( mom + son) must be create a momentum equal to the maximum momentum.
Heat engines were developed during industrial revolution.
Generally a heat engine contains three parts i.e source, sink and working substance.
The source of a heat engine is present at a higher temperature as compared to the sink. Due to the temperature difference, the heat will flow from source to sink through working substance.
Let us consider are the temperature of source and sink.
As the source is at higher temperature as compared to sink, heat will flow from source to sink.
are the heat provided by source and heat rejected to sink.
Hence, the work done by the working substance will be -
The efficiency of a heat engine is defined as the ratio of output to the input energy.
Here output = workdone [W]
Hence, the efficiency of a heat engine is calculated as -
This is the expression for the efficiency of heat engine.
Here, all the heat absorbed by the working substance can not be converted to desired output. The efficiency of a heat engine can not be 100 percent. Some amount of heat is lost in the form of sound and heat due to the friction which is produced due to the relative motion between various parts of the machine.
Answer:
Explanation:
The energy needed to ionize a hydrogen atom in the ground state is:
The energy of the photon is related to the wavelength by
where
h is the Planck constant
c is the speed of light
is the wavelength
Solving the formula for the wavelength, we find