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fredd [130]
3 years ago
10

A 500 kg car is moving at 30 m/s. The driver sees a barrier ahead. If the car takes 100 m to come to rest, what is the magnitude

of the force necessary to stop the car?
How do you solve this question?
Physics
1 answer:
FromTheMoon [43]3 years ago
7 0

Answer:

F = 2250 [N]

Explanation:

In order to solve this problem, we must first use the following equation of kinematics.

v_{f}^{2} =v_{o}^{2}-2*a*x

where:

Vf = final velocity = 0 (come to rest)

Vo =  initial velocity = 30 [m/s]

a = acceleration or desaceleration [m/s²]

x = distance = 100 [m]

(0)=30^{2} -2*a*100\\900 =  200*a\\a = 4.5 [m/s^{2}]

Now we must use the following equation of kinetics, which is based on Newton's second law that explains that the sum of forces on a body is equal to the product of mass by acceleration.

∑F = m*a

where:

F = force [N]

m = mass = 500 [kg]

a = acceleration = 4.5 [m/s²]

F = 500*4.5\\F = 2250 [N]

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This question apparently wants you to get comfortable
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c = 3 x 10⁸ m/s
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Divide each side by (3 x 10⁸ m/s)²:

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______________________________________

Something like this could have been much more impressive:
 
The Braidwood Nuclear Power Generating Station in northeastern
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<span>The station has two pressurized water reactors, which can generate
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If the Braidwood plant were able to completely convert mass
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             =  (2,242 x 10⁶ x 86,400 x 365) joules

             =          7.0704 x 10¹⁶ joules .

How much converted mass is that ?

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Divide each side by  c² :    Mass  =  E / c² .
c = 3 x 10⁸ m/s

              Mass = (7.0704 x 10¹⁶ joules) / (9 x 10¹⁶ m²/s²)

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THAT should impress us !  If I've done the arithmetic correctly,
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