If 50 identical light bulbs are connected in series across
a single power source, then the voltage across each bulb
is ( 1/50 ) of the voltage delivered by the power source.
The answer would be a radio wave
Answer:
![S_a_v_e_r_a_g_e=48km/h](https://tex.z-dn.net/?f=S_a_v_e_r_a_g_e%3D48km%2Fh)
Explanation:
Ok, the average speed can be calculate with the next equation:
(1)
Basically the car cover the same distance "d" two times, but at different speeds, so:
![Total\hspace{3}distance=2*d](https://tex.z-dn.net/?f=Total%5Chspace%7B3%7Ddistance%3D2%2Ad)
and the total time would be the time t1 required to go from A to B plus the time t2 required to go back from B to A:
![Total\hspace{3}time=t1+t2](https://tex.z-dn.net/?f=Total%5Chspace%7B3%7Dtime%3Dt1%2Bt2)
From basic physics we know:
![t=\frac{d}{S1}](https://tex.z-dn.net/?f=t%3D%5Cfrac%7Bd%7D%7BS1%7D)
so:
![t1=\frac{d}{S1}](https://tex.z-dn.net/?f=t1%3D%5Cfrac%7Bd%7D%7BS1%7D)
![t2=\frac{d}{S2}](https://tex.z-dn.net/?f=t2%3D%5Cfrac%7Bd%7D%7BS2%7D)
Using the previous information in equation (1)
![S_a_v_e_r_a_g_e=\frac{2*d}{\frac{d}{S1} +\frac{d}{S2} }=\frac{2*d}{\frac{d*S2+d*S1}{S1+S2} }](https://tex.z-dn.net/?f=S_a_v_e_r_a_g_e%3D%5Cfrac%7B2%2Ad%7D%7B%5Cfrac%7Bd%7D%7BS1%7D%20%2B%5Cfrac%7Bd%7D%7BS2%7D%20%7D%3D%5Cfrac%7B2%2Ad%7D%7B%5Cfrac%7Bd%2AS2%2Bd%2AS1%7D%7BS1%2BS2%7D%20%7D)
Factoring:
(2)
Finally, replacing the data in (2)
![S_a_v_e_r_a_g_e=\frac{2*40*60}{60+40} =48km/h](https://tex.z-dn.net/?f=S_a_v_e_r_a_g_e%3D%5Cfrac%7B2%2A40%2A60%7D%7B60%2B40%7D%20%3D48km%2Fh)
Answer: 0.9264 kg
Explanation: [I'll use "cc" for cubic centimeter, instead of cm^3.
The volume is 6cm*4cm*2cm = 48 cm^3 (cc).
Density of Au is 19.3 g/cc
Mass of gold = (48 cc)*(9.3 g/cc) = 926.4 grams Au
1 kg = 1,000 g
(926.4 grams Au)*(1 kg/1,000 g) = 0.9264 kg, 0.93 kg to 2 sig figs
At gold's current price of $57,500/kg, this bar is worth $53,268. Keep it hidden from your lab partner (and instructor).