Explanation:
a) The height of the ball h with respect to the reference line is

so its initial gravitational potential energy
is



b) To find the speed of the ball at the reference point, let's use the conservation law of energy:

We know that the initial kinetic energy
as well as its final gravitational potential energy
are zero so we can write the conservation law as

Note that the mass gets cancelled out and then we solve for the velocity v as



During a race, a sprinter accelerated 1.8 m/s 2 in 2.5 seconds. The sprint increase with this amount of acceleration by 4.5 m/s.
<h3>What is acceleration?</h3>
Acceleration is the time rate of change of velocity.
Acceleration a = velocity v / time t
1.8 = v/2.5
v = 4.5 m/s
The sprint increase with this amount of acceleration by 4.5 m/s.
Learn more about acceleration.
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Answer:
Conduction, Convection and Radiation
Explanation:
Hope this helps!
Answer:
That's simply because any electromagnetic wave longer than a microwave is called a radio wave. Microwaves: Obviously used for cooking in microwave ovens, but also for transmitting information in radar equipment. Microwaves are like short-wavelength radio waves. Typical size: 15cm (the length of a pencil).