Consider the train car described in the previous part. Another experiment is conducted in it: A net force of 20N is applied to a
1 answer:
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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.
Explanation:
1.
We use the equation
h = , where
h is the height traveled,
g is the acceleration due to gravity and
t is the time taken to reach height h.
We can now calculate t to be
= 0.495 s
Let v be the initial velocity of the player.
The player deaccelarates from v m/s to 0 m/s in 0.495 s at the rate of 9.81 m/s^2.
v = 9.81 m/s^2 x 0.495 s = 4.85 m/s
2.
The player takes 0.3 s to increase his velocity from 0 m/s to 4.85 m/s. So his average accelaration is
4.85 m/s / 0.3 s = 16.2 m/s^2