Answer:
Explanation:
As per the Kepler's law of planetary motions :
1- The orbits are of elliptical shape having two foci and Sun is located on one foci.
2- The line segment that joins a planet and the Sun sweeps out equal are at equal interval of time.
3- The orbital period square is directly proportional to the cube of semi major axis of its orbit.
Kepler's law are applied on each of the planets of our solar system as the distance of the Sun from the planet is calculated through this.
For example : from Kepler's first law we can see the eccentricity of the Earth's orbit is 0.0167.
Answer: A) length of string.
Answer: The frequency heard will be f = 275.675Hz
Explanation: When an object emitting sound is moving, it occurs a phenomenon called Doppler shift or Doppler effect. What happens is that the sound gets higher when the moving object comes closer the observer and becomes lower after it passes, This change is due to the quantity of waves that passes through an area in an unit of time.
The formula to calculate the Doppler effect is as follows
f = (
) · f₀
f is the observed frequency;
c is the speed of sound;
Vs is velocity of the source;
f₀ is the emitted frequency of source;
Substituting and calculating,
f =
· 300
f = 275.675 Hz
Thus, the frequency heard by the police officer is 275.675Hz.
Answer:
KE = incident energy - work function
The maximum KE will be (3 - .6) eV = 2.4 eV
The formula of the kinetic energy is KE = 0.5*m*v^2.
Given m = 80 kg and KE = 4000 J,
4000 = 0.5*80*v^2
v^2 = 100
v = 10 m/s