Answer:
Explanation:
Given
mass of boy 
mass of girl 
speed of girl after push 
Suppose speed of boy after push is 
initially momentum of system is zero so final momentum is also zero because momentum is conserved




i.e. velocity of boy is 2.82 m/s towards west
Answer:0.153 Hz
Explanation: The relation between Time Period(T) and frequency(f) is given by T=1/f
Plug in the values and u arrive at the answer
Larger molecules will move slower and smaller molecules will move faster. Did this answer your question?
Answer:
Speed of physicist car is 0.036c or 1.08 x 10⁷ m/s .
Explanation:
Doppler Effect is defined as the change in frequency or wavelength of the wave as the source or/and observer moving away or towards each other.
In this case, the Doppler effect equation in terms of wavelength is :
......(1)
Here
is source wavelength,
is observed wavelength, v is speed of the observer and c is the speed of light.
Given :
Source wavelength,
= 660 nm = 660 x 10⁻⁹ m
Observed wavelength,
= 555 nm = 555 x 10⁻⁹ m
Substitute these values in the equation (1).






v = 1.08 x 10⁷ m/s