Given :
Initial speed of car A is 15 m/s and initial speed of car B is zero.
Final speed of car A is zero and final speed of car B is 10 m/s.
To Find :
What fraction of the initial kinetic energy is lost in the collision.
Solution :
Initial kinetic energy is :
Final kinetic energy is :
Now, fraction of initial kinetic energy loss is :
Therefore, fraction of initial kinetic energy loss in the collision is 1.25 .
Answer: Current, resistance and voltage are the quantities which are related by Ohm's law.
Explanation:
A law which states that electric current is directly proportional to voltage and inversely proportional to resistance is called Ohm's law.
Mathematically, it is represented as follows.
where,
I = current
V = voltage
R = resistance
This means that the quantities related by Ohm's law include current, voltage and resistance.
Thus, we can conclude that current, resistance and voltage are the quantities which are related by Ohm's law.
Answer:
The observed frequency by the pedestrian is 424 Hz.
Explanation:
Given;
frequency of the source, Fs = 400 Hz
speed of the car as it approaches the stationary observer, Vs = 20 m/s
Based on Doppler effect, as the car the approaches the stationary observer, the observed frequency will be higher than the transmitted (source) frequency because of decrease in distance between the car and the observer.
The observed frequency is calculated as;
where;
F₀ is the observed frequency
v is the speed of sound in air = 340 m/s
F₀ ≅ 424 Hz.
Therefore, the observed frequency by the pedestrian is 424 Hz.