Answer:
m g = G * m * M / R^2 force of attraction
g = G * M / R^2
g = 6.67E-11 * 5.96E24 / (6.37E6)^2
g = 6.67 * 5.96 / 6.37^2 * 10^1
g = .98 * 10 = 9.8 m/s^2
Q2.
d g = G M * (-2 R^-3 dR ) = -2 G M / R^3 (very small where dR = 1)
Answer:
New force = 9(initial force)
Explanation:
The force between two charges is given by :

Where
d is the original distance
Let d' is the new distance such that, r' = r/3
New force,

So, the new force becomes 9 times the initial force.
Answer:
<h2>3.39 J</h2>
Explanation:
The kinetic energy of an object can be found by using the formula

m is the mass
v is the velocity
From the question we have

We have the final answer as
<h3>3.39 J</h3>
Hope this helps you
Answer:
D) 11 m/s
Explanation:
We have to calculate the velocity of the hot dog with respect to the observer still outside the train. This velocity will be given by:

where
is the velocity of the train (towards right)
is the velocity of the man (towards right)
is the velocity of the hot-dog (towards left, so we put a negative sign)
By replacing the numbers into the equation, we find

and the positive sign means the velocity is toward right.
Answer:
Explanation:
a )
one kg of coal gives energy of 27 x 10⁶ J
75 kg of coal gives energy of 27 x 10⁶ x 75 J
So rate which energy is coming out of coal per second
= 27 x 10⁶ x 75 J
= 2025 x 10⁶ J /s
2025 million watts .
b ) energy output = 800 million watts
efficiency = (800 / 2025) x 100
= 39.5 % .