I actually know the answer to this one, you use pennies to find the atomic weight of a penny, it really doesn't have a weight. LOL
Answer:
Explanation:
A charge is produced when an atom losses or gains an electron. The law of static electricity states that like charges repels, while unlike charges attracts.
1. To determine the charge on the polystyrene rod.
Place the polystyrene rod on the non-conducting rotating stand, and bring the positively charged rod close to it. If attraction occurs, it shows that it is oppositely charged. If repulsion occurs, it shows that it is positively charged.
Bringing a negatively charged rod close to the rotating polystyrene rod would attract it if the charge is opposite. But if the charge on the two rods are the same, repulsion occurs.
2a. When the polystyrene rod is positively charged, it would attract the negatively charged rod but repel the positively charged rod.
b. When the polystyrene rod is negatively charged, it would repel the negatively charged rod but attract the positively charged rod.
c. When the polystyrene rod is uncharged, no reaction would be observed when either the positively charged or negatively charged rod is brought close to it.
Answer:
1/3 times.
Explanation:
Let V₀ be the peak voltage .
IR ( rms ) = ( V₀ / √2 R )
R is value of resistance
IC = ( V₀ ωC / √2 )
( 1 / ωC is reactance of capacitance in ac circuit )
= 
When frequency is tripled angular frequency will also be tripled
hence the ratio 
becomes 1/3 times.
40 miles/hour
Details:
after one hour they have traveled 40mi. So they have traveled 40mi. in 1hr, or 40mi/1hr or 40mi/hr.
the problem is about reading a graph. the graph says that they traveled 40 miles in the first hour
formula for average speed:
miles traveled/time it took=speed or d/t=r
Answer:
Her angular speed (in rev/s) when her arms and one leg open outward is 1.4 rev/s
Explanation:
given information:
moment inertia of arm and leg when in, I₁ = 0.9 kgm²
moment inertia of arm and leg when extended, I₂ = 2.9 kgm²
angular speed when in, ω₁ = 4.5 rev/s
so, her angular speed (in rev/s) when her arms and one leg open outward is
L₁ = L₂
I₁ω₁ = I₂ω₂
ω₂ = I₁ω₁/I₂
= 0.9 x 4.5/2,9
= 1.4 rev/s
