Also, isn’t pe independent of the horizontal velocity. so shouldn’t the last question be all pe and no ke.
@ndterm But KE is dependent on velocity. The person has KE an instant after he leaves the airplane. Because of the plane’s velocity, he too has a velocity. So we should consider KE too.
What is the predicted curve for 800? 780?
What was the answer to the question about the satellite in elliptical orbit around a planet? It asked something about PE and speed, right?
Are these answers correct
11# B
12# A
and what about the energy changes as the parachutist fall? All PE?
Also there was another question of satellite orbiting earth in elliptical pathways what happens to its PE and speed as it comes near to Earth ? Should the speed increase?
I don’t know what happens to the PE but the speed increases because it has to cover more distance in a lesser amount of time (when compared to it being far away from the earth) because of Kepler’s 2nd law (A line segment joining a satellite and the planet sweeps out equal areas during equal intervals of time).
@seyll00 won’t that depend on the direction in which the diver jumps…if he jumps vertically, the horizontal ke won’t matter i guess…does someone remember if the direction he jumps in was mentioned in the question…shouldn’t that settle the debate?
@ndterm Even if he does jump vertically, he will have a horizontal velocity because of the plane’s velocity right? Did they asked for the energy an instant after he jumped? Because only then can we consider KE I guess.
I’m just gonna forget this question. XD I really can’t help my answers right now… lol.
I also think it is All PE, because PE = mgh and it is potential to do work, i.e gaining KE when falling, that’s why here initial horizontal velocity really don’t matter.
How about question with boy on merry-go-round, will it continue to move straight like
_|
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/
( P
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?
I think it’s All PE, because PE is potential to do work, i.e gain KE while falling from height, that’s why only vertical velocity matters. How about merry-go-round question? Will it move straight or bend a bit?
@exmazret Energy is a scalar. Therefore, no matter what direction the parachutist is moving in, he still has KE, because he has mass and a nonzero velocity. It’s not the same as forces, where ones that are perpendicular don’t matter. At least that’s what I’ve gathered from reading a few physics forum posts to sort this out.
If it said “from the reference point of someone I side the plane” then it might be different, as they are moving too, so they wouldn’t notice the horizontal velocity and therefore wouldn’t detect any KE. But I’m pretty sure it didn’t say that.
Also, the ball will go in a straight line, tangent to the point that it left the circle. This is because the centripetal force stops acting on it as soon as it is thrown.
What did you write for that Q… The perfectly polarising filter one? I wrote no light passes through it.
I wrote some of it…and for that ke and pe skydiving carping when we take the in tial point of reference as the plane the skydiver has a 0 velocity wrt the plane hence as he’s at a height he will have all pe and no ke.take for example a ball thrown horizontally at the point of release the ball though it has a velocity horizontally we use the equation mgh=.5mv^2
For that question, I put PE decreased and speed increased.
@ThugLife13 what we’re the options to that?cuz if an option half the amount is passed that’s the right answer
@Adityaskumar Im pretty sure it was none of it. Think of polarizing sunglasses
Do you remember the full question?
For the polarizer question, I put “some of the light will pass through”. Using the sunglasses example, light still has to pass through in order for you to see through it. @thetennisking
Guys how many could I miss to score at least a 700? I thought this test was pretty hard so the curve should be easier
@thetennisking sunglasses do polarizer it if it didn’t allow any light u cannot see anything just try to think about it…I could give a more scientific explanation if u want