Five soccer players argued about when a soccer ball has energy. This is what they said. Jorge: The ball has to be moving to have energy.
Kurt: The ball has energy only at the moment it is kicked,
Amos. The ball has energy only when it is not moving.
Alan: The ball has energy when it is moving and not moving
Flavio: The ball has no energy. There is no source of energy in the ball
os of the Max Compare
Alan
Who do you agree with the most?
Explain your thinking.
What rule or reasoning did you use to decide when the soccer ball has energy?
The
தே Í
13

Spend time observing or thinking about events that involve matter and energy. which events can you explain? which events can’t you explain?

What determines the amount of inertia an object has

Consider a double atwood machine constructed as follows: a mass 4m is suspended from a string that passes over a massless pulley on frictionless bearings. the other end of this string supports a second similar pulley, over which passes a second string supporting a mass of 3m at one end and m at the other. using two suitable generalized coordinates, set up the lagrangian and use the lagrange equations to find the acceleration of the mass 4m when the system is released. explain why the top pulley rotates even though it carries equal weights on each side.