Answer:
<em>The second ball has four times as much kinetic energy as the first ball.</em>
Explanation:
<u>Kinetic Energy
</u>
Is the type of energy an object has due to its state of motion. It's proportional to the square of the speed.
The equation for the kinetic energy is:

Where:
m = mass of the object
v = speed at which the object moves
The kinetic energy is expressed in Joules (J)
Two tennis balls have the same mass m and are served at speeds v1=30 m/s and v2=60 m/s.
The kinetic energy of the first ball is:



The kinetic energy of the second ball is:



Being m the same for both balls, the second ball has more kinetic energy than the first ball.
To find out how much, we find the ratio:

Simplifying:

The second ball has four times as much kinetic energy as the first ball.
Answer:
the eletrical forces are created when an object is both moving charges and stationary charges.
the magnetic forces are created when an act on only moving charges.
Errrrr, it has 80.
80 is the correct answer
Answer: Sara tries turning a test tube upside down to collect a gas.
A scientist is considered to be creative when he approaches a problem with new different ways. The conventional way is to design an experiment and take detailed notes, reading referenced studies previously done. Sara tries turning a test tube upside down to collect a gas is a creative way as Sara tries something different.