Aperson carries a plank of wood 2.00 m long with one hand pushing down on it at one end with a force f1 and the other hand holding it up at .500 m from the end of the plank with force f2 . if the plank has a mass of 20.0 kg and its center of gravity is at the middle of the plank, what are the magnitudes of the forces f1 and f2 ?

Explain the consequences of this addiction to the brain tissue

(2) (a) you have a simple circuit that consists of only a battery (δvbat=1.5v) and two resistors with resistance r1=10ω and r2=5ω, connected in series with each other. what is the current running through the battery? (b) you re-arrange your circuit so now r2 is attached in parallel to r1 rather than in series. what is the current running through the battery? (c) you add an additional resistor r3=7ω on the same branch as r2. what is the current running through the battery? (d) what is the power dissipated in r3?

Which of the following is the main energy source for the sun? a. fission of hydrogen b. fusion of hydrogen c. fusion of helium d. fission of iron