True or False: Car Collision Kinetic Energy and Rest

  • Thread starter PhysicsPhun
  • Start date
In summary, if the cars are at rest after the collision, then the final total kinetic energy of the car1-car2 system is less than the initial total kinetic energy of the two cars.
  • #1
PhysicsPhun
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A) If car 1 sticks to car 2, the final total kinetic energy of the car1-car2 system is less than the initial total kinetic energy of the two cars.
B) If car 1 sticks to car 2, the car1-car2 system must be at rest after the collision.
C) Suppose (for this statement only) that car 2 was NOT initially at rest, but was instead heading towards car 1 with equal (but opposite) momentum before the collision. After the collision, the cars must both be at rest.
D) If car 1 is much lighter than m2, and the collision is perfectly elastic, car 1 will continue heading to the right with nearly its original speed after the collision.
E) If the collision is elastic, car 1 must always come to a stop after the collision

Anyone have ideas on these?
 
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  • #3
A) If they stick together, it's an inelastic collision. What's a consequence (actually the definition) of an inelastic collision?

B) Conservation of momentum says...?

C) Conservation of momentum says...?

D) Which way did car 1 start out going? There's not enough information to answer it as it is.

E) Why would this be true?

cookiemonster
 
  • #4
In the context of your posts 'at rest' is poorly defined - does the excercise specify a reference frame?
 
  • #5
A car, mass m1 moves to the right on a frictionless air track. It collides with a second car, mass m2, which is initially at rest. Which of the following statements are true?

That is the Base of the Question. I left that out sorry.

From the help you guys gave, I'm thinking that the first is the only true statement.
 
  • #6
That's not quite right. More than just 1 of them is true.

cookiemonster
 

1. What is kinetic energy in a car collision?

Kinetic energy is the energy an object possesses due to its motion. In the context of a car collision, it refers to the energy that the car has due to its movement before the collision occurs.

2. Does kinetic energy affect the severity of a car collision?

Yes, kinetic energy plays a crucial role in determining the severity of a car collision. The greater the kinetic energy of the car, the more damage it can cause upon impact.

3. How does kinetic energy change during a car collision?

In a car collision, the kinetic energy of the car changes as it goes from a state of movement to a state of rest. Initially, the car has kinetic energy due to its motion, but during the collision, this energy is converted into other forms such as sound, heat, and deformation of the car and its surroundings.

4. Is there a relationship between the kinetic energy of two colliding cars?

Yes, the kinetic energy of two colliding cars is directly proportional to their masses and the square of their velocities. This means that the greater the mass and velocity of the cars, the more kinetic energy they will have upon collision.

5. Can kinetic energy be completely absorbed during a car collision?

No, kinetic energy cannot be completely absorbed during a car collision. Some of the energy will always be converted into other forms, such as sound and heat. However, the amount of energy that is absorbed can be minimized through safety features such as airbags and crumple zones in cars.

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