The answer is B. This form of magnesium chloride is not a liquid but a solid that is white and colorless.
This problem is a piece o' cake, IF you know the formulas for both kinetic energy and momentum. So here they are:
Kinetic energy = (1/2) · (mass) · (speed²)
Momentum = (mass) · (speed)
So, now ... We know that
==> mass = 15 kg, and
==> kinetic energy = 30 Joules
Take those pieces of info and pluggum into the formula for kinetic energy:
Kinetic energy = (1/2) · (mass) · (speed²)
30 Joules = (1/2) · (15 kg) · (speed²)
60 Joules = (15 kg) · (speed²)
4 m²/s² = speed²
Speed = 2 m/s
THAT's all you need ! Now you can find momentum:
Momentum = (mass) · (speed)
Momentum = (15 kg) · (2 m/s)
<em>Momentum = 30 kg·m/s</em>
<em>(Notice that in this problem, although their units are different, the magnitude of the KE is equal to the magnitude of the momentum. When I saw this, I wondered whether that's always true. So I did a little more work, and I found out that it isn't ... it's a coincidence that's true for this problem and some others, but it's usually not true.)</em>
The time for the police car to catch up with the speeding motorist is 7.6 seconds.
<h3>What time will the police car catch up with the speeding motorist?</h3>
The police car and the motorist will cover equal distances.
Let the distance covered be d.
Distance covered by the motorist = speed * time
time = t, speed = 30 m/s
d = 30t
Distance covered by the police car = acceleration * (time)
time = t - 2, acceleration = 5.0 m/s²
d = 5(t-2)²
d = 5(t² - 4t + 4)
d = 5t² - 20t + 20
Equating the two equations for distance
5t² - 20t + 20 = 30t
5t² - 50t + 20 = 0
Solving for t using the quadratic formula:
t = 9.6 second or 0.4 seconds
Since t > 2, t = 9.6 seconds
t - 2 = 9.6 - 2
t - 2 = 7.6 seconds
Therefore, the time for the police car to catch up with the speeding motorist is 7.6 seconds.
Learn more about distance and acceleration at: brainly.com/question/14344386
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