Ask Question
27 March, 02:55

Hi so I have to do a project about like momentum and stuff and I was wondering when you throw a tennis ball (like to your dog or something) is there a collision and if so would it be elastic or inelastic? Sorry I know this is a lot I am just very confused.

+1
Answers (2)
  1. 27 March, 02:59
    0
    A collision is simply when there are two objects involved,

    at least one of them is moving, and they bump together.

    An elastic collision is one in which no kinetic energy is lost,

    so the total kinetic energy after the collision is the same as

    it was before.

    In real life on Earth, there's always some friction during the

    collision, and friction robs kinetic energy, so no collision is

    ever perfectly elastic. Whenever you get a school Physics

    problem that involves a collision, the problem will always tell

    you when you're supposed to assume that it's elastic. When

    you see that, it's a big green flag that tells you that you can

    probably make a bee-line straight to the answer if you just

    write down the kinetic energy before, the kinetic energy after,

    and set them equal.

    Your example:

    You throw a tennis ball to your dog.

    A very complicated situation!

    First, when is there a collision?

    - - If the ball bounces before the dog gets it, there's a collision

    between the ball and the ground.

    Kinetic energy is gained as gravity pulls the ball down to the

    ground. Kinetic energy is lost to friction in the bounce, when

    all the little hairs on the tennis ball scrape against concrete or

    blades of grass. Energy is also lost because the ball smooshes

    against the ground and then springs back to being a ball. The

    squeezing and stretching of the rubber swallows some energy.

    That's why a ball never bounces back as high as you drop it from.

    - - Another collision when the dog snatches the ball out of the air

    and it sticks in his mouth.

    If the dog was hanging from a rope or a harness and was free to

    swing, this might actually be almost an elastic collision. After he

    caught the ball, the dog would swing with all the kinetic energy

    that he got from the ball.

    But he's not free to swing, and he doesn't go anywhere after he

    catches the ball. What happened to the kinetic energy of the ball?

    It was immediately absorbed by the dog's neck muscles, and there's

    none left. So the kinetic energy after that collision is zero, and the

    collision is definitely not elastic.

    Whenever you need to decide, look at the kinetic energy before

    and after. Remember, kinetic energy of each moving object is

    (1/2) x (mass) x (speed squared).

    If the total kinetic energy of all moving objects is the same before

    and after the collision, then the collision was elastic.
  2. 27 March, 03:25
    0
    There is collision with an object that hits
Know the Answer?
Not Sure About the Answer?
Find an answer to your question 👍 “Hi so I have to do a project about like momentum and stuff and I was wondering when you throw a tennis ball (like to your dog or something) ...” in 📗 Physics if the answers seem to be not correct or there’s no answer. Try a smart search to find answers to similar questions.
Search for Other Answers