How Fast Was Anna Driving Before the Collision?

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In summary, Anna left her home in a hurry and collided with a stalled car on the street. The cops determined that the two vehicles moved together for 2 meters at a speed of 0.05 m/s after the collision. Using the momentum equation, we can calculate that Anna's velocity before the collision was also 0.05 m/s. This collision can be classified as elastic since the total momentum before and after the collision is the same. To understand how to solve momentum problems, you can use the momentum equation and compare the total momentum before and after the collision.
  • #1
wonderclass07
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1. One early morning a young woman, Anna, left her home for work in a hurry. She didnt know how fast she was driving and she didn't see the stalled car on the street until she runs into it. When the copscame they determined that the two vihecles must have moved togather for about 2 meters distance at o.o5 m/s after collision. The mass of Anna's car is 300kg and the mass of the stalled car is 200kg. You are given this information to calculate how fast Anna was driving before collision



2. Is this kind of collision elastic or inelastic?



3. For some reason i fail to understand momentum problems. I would love to understand how to do this. Help!
 
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  • #2
Momentum problems can be solved using the momentum equation, which states that the momentum of an object is equal to its mass times its velocity. Therefore, to solve a momentum problem, you will need to determine the mass and velocity of each object before and after the collision. Then, use the equation to calculate the total momentum before and after the collision and compare them. If the total momentum before and after the collision is the same, then the collision is said to be elastic. If the total momentum before and after the collision is not the same, then the collision is said to be inelastic. To solve the specific problem given above, we can use the momentum equation to calculate Anna's velocity before the collision: V1 = (m1v1 + m2v2)/m1 where m1 is the mass of Anna's car (300kg), v1 is the velocity of Anna's car before the collision (unknown), m2 is the mass of the stalled car (200kg), and v2 is the velocity of the stalled car before the collision (0). Plugging in the values, we get: V1 = (300*v1 + 200*0)/300 V1 = v1 Therefore, Anna's velocity before the collision was 0.05 m/s.
 
  • #3


1. I would first calculate the momentum of the two vehicles before the collision using the formula p=mv, where p is momentum, m is mass, and v is velocity. We know the mass of both vehicles and the final velocity after the collision, so we can solve for the initial velocity (v). The equation would be: 300kg(v) + 200kg(0) = (300kg + 200kg)(0.05m/s). Solving for v, we get v=0.0333 m/s. Therefore, Anna's car was traveling at a speed of 0.0333 m/s before the collision.

2. This type of collision is inelastic. In an elastic collision, the kinetic energy of the objects is conserved, meaning it stays the same before and after the collision. In an inelastic collision, some of the kinetic energy is lost and converted into other forms of energy, such as heat or sound. In this scenario, the two cars stuck together after the collision, indicating that some of the kinetic energy was lost and not conserved.

3. Momentum problems can be challenging, but they follow a simple formula and require basic algebra skills. The key is to remember that momentum is conserved in a closed system, meaning it stays the same before and after a collision. In this case, we can use the formula p=mv to solve for the initial velocity of Anna's car. If you are still struggling, I would suggest seeking help from a tutor or watching online tutorials to better understand the concept and practice solving similar problems.
 

Related to How Fast Was Anna Driving Before the Collision?

1. What is the meaning of "V before collision" in physics?

"V before collision" refers to the velocity or speed of an object before it collides with another object in a physics problem. It is an important factor in determining the outcome of the collision.

2. How is "V before collision" calculated?

The calculation of "V before collision" depends on the given information in the problem. It can be calculated using the formula V = d/t, where V is the velocity, d is the distance traveled, and t is the time taken. Alternatively, it can also be calculated using the formula V = m/s, where V is the velocity, m is the mass of the object, and s is the initial speed.

3. What are the units for "V before collision" in physics?

The units for "V before collision" in physics are typically meters per second (m/s) or kilometers per hour (km/h). However, depending on the given information and the units used for other variables, the units for "V before collision" may vary.

4. How does "V before collision" affect the outcome of a collision?

The velocity of an object before a collision directly impacts the momentum and kinetic energy of that object. This, in turn, affects the outcome of the collision. A higher "V before collision" will result in a greater momentum and kinetic energy, potentially causing more damage or a more significant change in the object's direction after the collision.

5. Can "V before collision" be negative?

Yes, "V before collision" can be negative if the object is moving in the opposite direction of the collision. In this case, the negative sign indicates that the object is moving in the opposite direction of the positive direction used in the calculation.

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