A0.10 kg meter stick is held perpendicular to a vertical wall by a 2.5 mm string going from the wall to the far end of the stick.
(a) find the tension in the string.
(b) if a shorter string is used, will its tension be greater than, less than, or the same as that found in part (a)?
(c) find the tension in a 2.0 m string.

Which is not a source of noise pollution? a)airplanes b)acid rain c)machines d)cars

Could someone . i have tried to solve myself but my calculation is off

(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?