Answer:

Explanation:
For the simple pendulum problem we need to remember that:
,
where
is the angular position, t is time, g is the gravity, and L is the length of the pendulum. We also need to remember that there is a relationship between the angular frequency and the length of the pendulum:
,
where
is the angular frequency.
There is also an equation that relates the oscillation period and the angular frequeny:
,
where T is the oscillation period. Now, we can easily solve for L:

Answer:
<h3> 1.40625m/s²</h3>
Explanation:
Using the equation of motion expressed as v = u+gt where;
v is the final velocity of the ball
u is the initial velocity
g is the acceleration due to gravity
t is the time taken
Given
u = 9m/s
v = 0m/s
t = 6.4s
Required
acceleration due to gravity g
Since the rock is thrown up, g will be a negative value.
v = u+(-g)t
0 = 9-6.4g
-9 = -6.4g
6.4g = 9
divide both sides by 6.4
6.4g/6.4 = 9/6.4
g = 1.40625m/s²
Hence the acceleration due to gravity on the planet is 1.40625m/s²
PART a)
Before Drew throw Lily in forwards direction they both stays at rest
So initial speed of both of them is zero
So here we can say that initial momentum of both of them is zero
So total momentum of the system initially = ZERO
PART b)
Since there is no external force on the system of two
so there will be no change in the momentum of this system and it will remain same as initial momentum
So final momentum of both of them will be ZERO
PART c)
As we know that momentum of both will be zero always
so we have


in opposite direction
Answer:
Hydroelectricity is a renewable energy source.
Hydroelectricity increases the stability and reliability of electricity system
Hydroelectricity helps fight climate changes.
Explanation:
If we use hydroelectricity our country would be in good climate and not a bad one. And the best facts it is renewable.