Answer:
T/√8
Explanation:
From Kepler's law, T² ∝ R³ where T = period of planet and R = radius of planet.
For planet A, period = T and radius = 2R.
For planet B, period = T' and radius = R.
So, T²/R³ = k
So, T²/(2R)³ = T'²/R³
T'² = T²R³/(2R)³
T'² = T²/8
T' = T/√8
So, the number of hours it takes Planet B to complete one revolution around the star is T/√8
Answer:
Explanation:
The standard equation of the sinusoidal wave in one dimension is given by

Here, A be the amplitude of the wave
λ be the wavelength of the wave
v be the velocity of the wave
Φ be the phase angle
x be the position of the wave
t be the time
this wave is travelling along positive direction of X axis
The frequency of wave is f which relates with velocity and wavelength as given below
v = f x λ
The relation between the time period and the frequency is
f = 1 / T.
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:
B
Explanation:
Displacement is the distance from the start point to the endpoint, displacement disregard the path taken or the amount traveled.
if you start at point A, then go to point B, and back to point A, the displacement is zero because you started and ended at the same point.
for this question, pretend you started at point A, went east 20 km to point B, and then west 8 km to point C, your displacement is 12 km. 12 km is the distance between point A and point C.