The original gravity is 10 or 9.8 (whatever you want, 10 creates less messy numbers lol).
Equations of motion are:
Nope. It's beyond the scope of the course though. You need 4u maffs to do it.Equations of motion are:
x = 0
y = Vt - 4.9t^2
y = 10t - 4.9t^2
vertical velocity is given by: Vy = 10 - 9.8t
Ball reaches maximum height when Vy = 0
i.e. 0 = 10 - 9.8t
t = 1.0204 seconds
then silly Mysterious S decides to be a kent and reduces radius of earth to 6400000/4
now to find our new g, we use g = GM/r^2
g = 6.67*10^-11*6*10^24/(1600000^2)
g = 156.33 ms^-1 (we feel realllyy fat)
so new equation of vertical motion (which is all we need) is y = 10t - 156.33/2 *t^2
when y = 0,
0 = 10t - 78.165*t^2
0 = t[10 - 78.165t]
t = 0 is when we launched so we use t = 0.1279
but t = 0.1279 is the total time of flight, and we only need half, so t = 0.06395
Then for total time we add our time with normal gravity with our time for crazy gravity and we get
t = 1.0204 + 0.06395
t = 1.08 seconds
hopefully thats right cause this was a pain to type up
That looks about right, nice workEquations of motion are:
x = 0
y = Vt - 4.9t^2
y = 10t - 4.9t^2
vertical velocity is given by: Vy = 10 - 9.8t
Ball reaches maximum height when Vy = 0
i.e. 0 = 10 - 9.8t
t = 1.0204 seconds
then silly Mysterious S decides to be a kent and reduces radius of earth to 6400000/4
now to find our new g, we use g = GM/r^2
g = 6.67*10^-11*6*10^24/(1600000^2)
g = 156.33 ms^-1 (we feel realllyy fat)
so new equation of vertical motion (which is all we need) is y = 10t - 156.33/2 *t^2
when y = 0,
0 = 10t - 78.165*t^2
0 = t[10 - 78.165t]
t = 0 is when we launched so we use t = 0.1279
but t = 0.1279 is the total time of flight, and we only need half, so t = 0.06395
Then for total time we add our time with normal gravity with our time for crazy gravity and we get
t = 1.0204 + 0.06395
t = 1.08 seconds
hopefully thats right cause this was a pain to type up
Well the way I saw it, first find the time taken for the projectile to reach max height, under gravity 10, it takes 1 second. Now lets find the new gravity of the earth, using our formula. We find it to be 160. Then substitute into our displacement equation for y again, and done, finding 0.25 seconds, add together 1.25 seconds?
The force due to gravity doesn't change simply because you've shrunk the earth. It's proportional to the distance from the centre of mass, which wouldn't change since you said it maintains its shape.That looks about right, nice work
Ill post another question soon (part 2 of Mysterious S's adventure!)
To do it properly you'd need to take into account that acceleration is proportional to the inverse square of the distance from the centre of mass and then do entirely new equations of motion. Any other way is going get a totally wrong answer because of the large distances involved. It's still a very good question though, just more suited for 4U.
1. Maxwell predicted that since a changing electric current induced a magnetic field and a changing magnetic field induced an electric current, then theoretically electromagnetic waves should be able to self- propogate throughout space. Hertz used a high voltage induction coil in order to create an oscillating electric field-> this changing electric field induced an oscillating electric spark in a receiving coil (draw diagram). He then reflected the created EMR (radio waves) off a metal plate into the receiving coil in order to create intereference effects between the original EMR and the reflected EMR. Through considering this EMR, he was able to determine the wavelength of the radio waves. The frequencey of the waves was the same as the frequency of the induction coil so that was already known. Through using the equation v=f(lambda), he was thus able to generate a value for the speed of EMR- roughly 3x10^8 m/s.
For question 2 the question is saying how..... would you need to go into modes and how energy can only be absorbed in equal multiples of lambda. Than explain how excitation occurs at different band levels causing the energy absorbed to be dependant on the position of the electron on the shell. i.e since the electrons cannot be in the forbidden gap, the energy absorbed can only be in discrete quantities....
Ah yes- cheers
How would you write the bolded bit as an answer? Thanks broOk here's a diagram:
p-n junction is just a p type and n type joined together. This essentially forms solar cells.
Careful. The p/n type semiconductors only gain a charge very close to the junction, in the depletion zone. The rest of them remains neutral, as far as I know.Ok here's a diagram:
Basically at the start, you have a P type semiconductor and an N-type semiconductor. The P type has an excess of positive holes and the N-type electrons. Now the some of the electrons from the N- type diffuse into the P-type and some of the holes from the P-type diffuse into the N-type. This makes the N-type side positively charged and the P-type side negatively charged. It also establishes an electric field in between them known as the depletion zone.
(Diagram) The Law of Conservation of Momentum states that total momentum must remain constant (i.e. P-rocket + P-exhaust = 0). As the rocket flies, it burns fuel, causing it to lose mass. This means that, as the momentum of the exhaust remains constant, the velocity of the rocket must increase (mv-rocket + mv-exhaust = 0). (If worth more marks: engage F=ma/g-force choip).
Thompson used a modified CRT, fitted with a collimator, magnetic (hemmaholtz) coils and electric plates, to define the charge to mass ratio. First he equated the force on the cathode ray due to the magnetic and electric fields respectively, such that the beam passed through unaffected. This allowed him to mathematically derive the velocity of the particles by equating the two formulas (qvB=qE). He then switched off the electric plates and measured the radius of the path of the cathode ray, due to the magnetic field alone. By combining the two aforementioned results (i.e. velocity and radius) he was able to define the charge to mass ratio. (q/m = v/Br)
