<span>A mechanical wave is a wave that is not capable of transmitting its energy through a vacuum. Mechanical waves require a medium in order to transport their energy from one location to another. A sound wave is an example of a mechanical wave.</span>
Answer: Often lightning occurs between clouds or inside a cloud. But the lightning we usually care about most is the lightning that goes from clouds to ground.
Explanation: As the storm moves over the ground, the strong negative charge in the cloud attracts positive charges in the ground.
Ok so we know:
The time (t) is 18seconds
The acceleration (a) is 2.2m/s2
The displacement (r) is 660
Using the equation

With 'u' being the initial velocity we want, we get:

So:

So:

So the original/initial velocity was 16.8666 or 16.87 m/s
Hope this helped
Answer:
a) 2 m/s
b) i) 
ii) 
Explanation:
The function for distance is 
We know that:
Velocity = 
Acceleration = 
To find speed at time t = 0, we derivate the distance function:

Substitute t = 0 in velocity function:

Velocity at t = 0 will be 2 m/s.
To find the function for Kinetic Energy of the box at any time, t.

We know that 

