Explanation:
The orbital radius of the Earth is 
The orbital radius of the Mercury is 
The orbital radius of the Pluto is 
We need to find the time required for light to travel from the Sun to each of the three planets.
(a) For Sun -Earth,
Kepler's third law :

M is mass of sun, 
So,

(b) For Sun -Mercury,

(c) For Sun-Pluto,

5.1 m
Explanation:
Let's set the ground as our reference point. Let's also call the dropped ball to be ball #1 and its height above the ground at any time t is given by
(1)
where 10 represents its initial height or displacement of 10 m above the ground. At the same time, the displacement of the second ball with respect to the ground
is given by
(2)
At the instant the two balls collide, they will have the same displacement, therefore

or

Solving for t, we get

We can use either Eqn(1) or Eqn(2) to hind the height where they collide. Let's use Eqn(1):


The car will move in a speed of 45 meter per second
Answer:
C
Explanation:
i could be wrong but it seems the most logical
Answer:
Net force will be 4.875 N
Explanation:
We have given mass of the cart m = 1.5 kg
Initial velocity of the cart = 0.2 m/sec
And final velocity of the car = - 0.125 m/sec ( Negative direction is due to opposite direction )
Instant of time 
Change in momentum is given by

Now force is given by

Net force will be 4.875 N