Answer:
a) 4 s
b) 36 m/s²
c) 54 m
Explanation:
s = 2t³ – 24t + 6
a) Find t when v = 72 m/s.
v = ds/dt
v = 6t² – 24
72 = 6t² – 24
6t² = 96
t = 4
b) Find a when v = 30 m/s.
a = dv/dt
a = 12t
When v = 30:
30 = 6t² – 24
6t² = 54
t = 3
a = 36
c) Find Δs between t = 1 and t = 4
Δs = (2(4)³ – 24(4) + 6) – (2(1)³ – 24(1) + 6)
Δs = 38 – (-16)
Δs = 54
<span>Depends on the precision you're working to.
proton mass ~ 1.00728 amu
neutron mass ~ 1.00866 amu
electron mass ~ electron mass = 0.000549 amu
Binding mass is:
mass of constituents - mass of atom
Eg for nitrogen:
(7*1.00728)-(7*1.00866)-(7*0.000549)
-14.003074 = 0.11235amu
Binding energy is:
E=mc^2 where c is the speed of light. Nuclear physics is usually done in MeV[1] where 1 amu is about 931.5MeV/c^2. So:
0.11235 * 931.5 = 104.6MeV
Binding energy per nucleon is total energy divided by number of nucleons. 104.6/14 = 7.47MeV
This is probably about right; it sounds like the right size!
Do the same thing for D/E/F and recheck using your numbers & you shouldn't go far wrong :)
1 - have you done this? MeV is Mega electron Volts, where one electronVolt (or eV) is the change in potential energy by moving one electron up a 1 volt potential. ie energy = charge * potential, so 1eV is about 1.6x10^-19J (the same number as the charge of an electron but in Joules).
It's a measure of energy, but by E=mc^2 you can swap between energy and mass using the c^2 factor. Most nuclear physicists report mass in units of MeV/c^2 - so you know that its rest mass energy is that number in MeV.</span>
Answer:
f'= 607.8 Hz
Explanation:
This is a Doppler effect exercise due to the relative velocity of the sound source and the observer.
By the time the source and the observer are getting closer the expression is
f ’=
where vs is the speed of the source, vo is the speed of the observer, if the bodies move away the signs are exchanged
in this case, train 1 emits sound, so its speed is v_s = 30.3 m / s and train 2 is the receiver of the sound v₀ = 22.5 m / s
let's calculate
f ’= 
520 (343+ 22.5 / 343 - 30.3)
f'= 607.8 Hz
It’s definitely D: seeing all the options available to you and giving one a try
