Answer:
The correct option is (B).
Explanation:
The Kepler's third law of motion gives the relationship between the orbital time period and the distance from the semi major axis such that,

It is mentioned that, an asteroid with an orbital period of 8 years. So,

So, an asteroid with an orbital period of 8 years lies at an average distance from the Sun equal to 4 astronomical units.
To solve this problem it is necessary to apply the concepts related to Newton's second law and the kinematic equations of movement description.
Newton's second law is defined as

Where,
m = mass
a = acceleration
From this equation we can figure the acceleration out, then



From the cinematic equations of motion we know that

Where,
Final velocity
Initial velocity
a = acceleration
x = displacement
There is not Final velocity and the acceleration is equal to the gravity, then





From the equation of motion where acceleration is equal to the velocity in function of time we have




Therefore the time required is 0.0705s
Answer:
Explanation:
Solution is in the picture attached
Answer:
3×10^7 m/s or 0.10c (e)
Explanation: If the actual value of the speed of light were to be put into consideration.
Given that the speed of light is c = 3.0×10^8m/s
The alien spaceship is approaching at the rate of 10% of the speed of light.
10% of 3.0×10^8m/s
10/100 × 3.0×10^8m/s
0.1 ×3.0×10^8m/s
3×10^7 m/s. Which is the same thing as 0.1 of c = 0.1×c
The sound is increased because sound waves are in fact mech. waves which means the that they can't travel through empty space and thus need a medium to travel through