Two steel balls collide and bounce apart in an isolated system. If the final kinetic energy is less than the initial kinetic energy, what of the following is true?
a) Momentum is conserved in this elastic collision incorrect
b) Momentum is not conserved in this elastic collision
c) Momentum is conserved in this inelastic collision
d) Momentum is not conserved in this inelastic collision
I selected a), and it was wrong. My understanding is that momentum is always conserved. Is that correct? Also, how do I distinguish between elastic and inelastic collisions?
thank you!
on answer a, it stated conserved in this elastic...it is NOT elastic collision.
try answer c)
Momentum is always conserved.
Yes, your understanding is correct. In any collision, the total momentum of the system is always conserved. Therefore, momentum is always conserved, regardless of whether the collision is elastic or inelastic.
The key difference between elastic and inelastic collisions lies in how kinetic energy is conserved during the collision.
In an elastic collision, both momentum and kinetic energy are conserved. This means that the total kinetic energy before the collision is equal to the total kinetic energy after the collision. In other words, the objects bounce off each other without any loss of energy.
In an inelastic collision, momentum is still conserved, but kinetic energy is not. Some of the initial kinetic energy is converted into other forms of energy, such as heat or sound, during the collision. As a result, the final kinetic energy is less than the initial kinetic energy.
Based on this information, the correct answer to the question is option (d) - Momentum is not conserved in this inelastic collision.
Your understanding that momentum is always conserved is correct. Momentum is a fundamental concept in physics and according to the law of conservation of momentum, the total momentum of an isolated system remains constant before and after a collision. Therefore, even in the case of collisions where the final kinetic energy is less than the initial kinetic energy, momentum is still conserved.
Now, let's distinguish between elastic and inelastic collisions:
- Elastic collisions: In elastic collisions, both momentum and kinetic energy are conserved. This means that the total kinetic energy before the collision is equal to the total kinetic energy after the collision. In an elastic collision, the objects bounce off each other without any deformation.
- Inelastic collisions: In inelastic collisions, momentum is still conserved, but kinetic energy is not. This means that the total kinetic energy after the collision is less than the total kinetic energy before the collision. In an inelastic collision, the objects stick together or deform during the collision.
In your scenario, if the final kinetic energy is less than the initial kinetic energy, the collision is inelastic. So, the correct answer is d) Momentum is not conserved in this inelastic collision.
Remember, while momentum is always conserved, kinetic energy can change depending on the type of collision.