Answer: a) 12 Ω; b) 15.10 m; c) 360 kJ
Explanation: In order to explain this problem we have to considere the OHM law which is given by:
V=R*I where R is the resistance and I the current, V is the voltage.
For the toaster heating the resistance must be equal
R=V/I=120/10= 12 Ω
We also know that R=ρ*L/A where L and A are the length and area of the wire.
Then the length of the wire is given by:
L=R*A/ρ= 12*π*(0.8*10^-3)^2/1.6*10^-6=15.10 m
Finally we can calculate the consumed energy by the toaster heating during 5 minutes (5*60s=300 s).
The power is equal:
P=I*V= 10*120=1200 W
E= P*time (s)= 1200*300=360*10^3J
Gravity is directly proportional to the product of the two. Masses and inversely proportional to the square distance between the two masses.
Main sequence stars fuse hydrogen atoms to form helium atoms in their cores. About 90 percent of the stars in the universe, including the sun, are main sequence stars. These stars can range from about a tenth of the mass of the sun to up to 200 times as massive. Stars start their lives as clouds of dust and gas.
