Answer:
Increase 9 times
Explanation:
We have Newton formula for attraction force between 2 objects with mass and a distance between them:

where
is the gravitational constant.
is the masses of the 2 objects. and R is the distance between them.
Since the force is inversely proportional to the distance squared, if it is reduced by 3 times, the gravitational force between them would increase by
times
Answer:
19.53 cm
Explanation:
The computation of the height is as follows:
Here we applied the conservation of the energy formula
As we know that
P.E of the block = P.E of the spring
m g h = ( 1 ÷ 2) k x^2
where
m = 0.15
g = 9.81
k = 420
x = 0.037
So now put the values to the above formula
(0.15) (9.81) (h) = 1 ÷2 × 420 × (0.037)^2
1.4715 (h) = 0.28749
h = 0.19537 m
= 19.53 cm
That is meters per second, same as velocity.
Answer:
The fraction fraction of the final energy is stored in an initially uncharged capacitor after it has been charging for 3.0 time constants is

Explanation:
From the question we are told that
The time constant 
The potential across the capacitor can be mathematically represented as

Where
is the voltage of the capacitor when it is fully charged
So at


Generally energy stored in a capacitor is mathematically represented as

In this equation the energy stored is directly proportional to the the square of the potential across the capacitor
Now since capacitance is constant at
The energy stored can be evaluated at as


Hence the fraction of the energy stored in an initially uncharged capacitor is
