Waves transfer energy not matter. so simply put, the water doesn't move. it's just being used as a road that energy uses to get from point a to b. it's easier to think of some thing on the water rather than the water it self. like a cork floating on the surface. when a wave passes through the cork. the cork goes up to the peak of the wave and then down to the trough of the wave and then back at equilibrium. it only moved up and down since it was following the wave pattern. if the waves transfered matter as well as energy then the cork would begin to get pushed by the wave and move towards the direction of travel
We can do this with the conservation of momentum. The fact it is elastic means no KE is lost so we don't have to worry about the loss due to sound energy etc.
Firstly, let's calculate the momentum of both objects using p=mv:
Object 1:
p = 0.75 x 8.5 = 6.375 kgm/s
Object 2 (we will make this one negative as it is travelling in the opposite direction):
p = 0.65 x -(7.2) = -4.68 kgm/s
Based on this we know that the momentum is going to be in the direction of object one, and will be 6.375-4.68=1.695 kgm/s
Substituting this into p=mv again:
1.695 = (0.75+0.65) x v
Note I assume here the objects stick together, it doesn't specify - it should!
1.695 = 1.4v
v=1.695/1.4 = 1.2 m/s to the right (to 2sf)
In a series circuit, each circuit element has the same current. The answer
is letter A. This is because the electrons flowing in a current has only a
single path to follow. There are no other path that the current moves along.
Energy transfer by waves: two primary modes = (electromagnetic waves, compression/transverse waves propagating through a medium)
1) electromagnetic waves:
Using a particle model for the wave (photons for light), energy transfer is similar to that by discrete moving object -- particles carry the energy from one place to another in the absence of a medium.
Energy delivery: discrete moving object uses inertia and momentum to transfer the energy from itself to the target. Photons are massless, so the energy delivery mechanism must be different.
2) compression/transverse waves propagating through a medium:
Energy passes through the medium with little to no net flow of the medium itself. In transverse water waves, when the energy wave passes by, to first order, the water particles move in vertical circular paths. This is different from energy transfer by a moving object in that the moving object must displace itself to the target position in order to deliver the energy -- resulting in a net flow of object material.
Answer:
A or B depending on your precision
Explanation:
In real life, applying to solid will shrink it depending on the amount of pressure applied, but due to the strength of solid bonds, the volume change is often negligible in practical situation and would only be accounted under astronomically high pressure phenomena (eg. at Jupiter's core or near black hole).
In high school level, and for many applications, it is entirely viable to completely neglect the change in solid volume under pressure. Thus, A is a legitimate answer. However, bear in mind that <em>in theory</em> the volume still decreases by a very slight amount. So B is correct as well, theoretically. The most correct option depends on the precision you needed.
