Answer:

Explanation:
As we know that the satellite revolves around the planet then the centripetal force for the satellite is due to gravitational attraction force of the planet
So here we will have

here we have


here we have

now we can find time period as




Now the density is given as



Answer: the answer is D. Aluminum and nitrogen
Explanation:
Answer:

Explanation:
We are given that
The wavelength of sound wave=
1 cm/s=
Speed of sound wave,v=
We have to find the period of the wave.
We know that
Frequency=
Using the formula
Frequency =
Hz
Time period=
Using identity:
Hence, the time period of the wave=
false. all obejects in motion have friction
Answer:
The answer is t = 23.81 s
Explanation:
A car in this question means those partition that make up the train
Let denote the the of each car as Z
The equation of motion that has to do with distance is given as
S = ut + (1/2)at²
Where u = initial velocity = 0
t = time = 9 s
Substituting these values we have
Z = (1/2) a(9)²
= 40.5 a
making acceleration the subject we have that a = Z / 40.5
Let us denote the length of the 7th car as =7Z
Considering the distance at the 7th car we have
S₇ = ut₇ + (1/2)at²₇
Where u = initial velocity =0
Substituting values we have
7Z = (1/2)(Z/40.5)(t₇)²
7 = {1/2 ×40.5}(t₇)²
t₇² = 7 × 2 × 40.5
t₇² = 567
t₇ = 23.81 s