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The parking brake on a 2000 kg Cadillac has failed, and it is rolling slowly, at 3.00 mph , toward a group of small children. Seeing the situation, you realize you have just enough time to drive your 2000 kg Volkswagen head-on into the Cadillac and save the children.

With what speed should you impact the Cadillac to bring it to a halt?

1 Answer

3 votes

Final answer:

The mass of Cadillac x velocity of Cadillac before collision = (mass of Cadillac + mass of Volkswagen) x velocity of combined vehicles after collision .To bring the rolling Cadillac to a halt and save the children, you should impact the Cadillac at a speed of 0.67 m/s.

Step-by-step explanation:

To bring the rolling Cadillac to a halt, you would need to determine the speed at which your Volkswagen should impact it.

This can be done by using the principle of conservation of momentum.

Since the Cadillac has a mass of 2000 kg and is rolling at 3.00 mph, we first convert its speed to meters per second: 3.00 mph = 1.34 m/s.

To calculate the required impact speed, we need to set up an equation using the momentum of the Cadillac before and after the collision:

momentum before collision = momentum after collision

This equation can be written as:

mass of Cadillac x velocity of Cadillac before collision = (mass of Cadillac + mass of Volkswagen) x velocity of combined vehicles after collision

Plugging in the known values, we get:

2000 kg x 1.34 m/s = (2000 kg + 2000 kg) x final velocity of combined vehicles

Simplifying the equation, we solve for the final velocity:

final velocity = (2000 kg x 1.34 m/s) / (2000 kg + 2000 kg)

Simplifying further, we get:

final velocity = 1.34 m/s / 2

final velocity = 0.67 m/s

Therefore, you should impact the Cadillac at a speed of 0.67 m/s in order to bring it to a halt and save the children.

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