Answer:
30 miliAmps
Explanation:
Step 1:
Obtaining an expression to solve the question. This is illustrated below:
From ohm's law,
V = IR
Were:
V is the voltage.
I is the current.
R is resistance.
From the question given, we were told that the resistance is constant. Therefore the above equation can be written as shown below:
V = IR
V/I = constant
V1/I1 = V2/I2
V1 is initial voltage.
V2 final voltage.
I1 is initial current.
I2 final current.
Step 2:
Data obtained from the question. This include the following:
Initial voltage (V1) = V
Initial current (I1) = 60 miliAmps
Final voltage (V2) = one-half of the original voltage = 1/2V = V/2
Final current (I2) =..?
Step 3:
Determination of the new current. This can be obtained as follow:
V1/I1 = V2/I2
V/60 = (V/2) / I2
Cross multiply to express in linear form
V x I2 = V/2 x 60
V x I2 = V x 30
Divide both side by V
I2 = (V x 30)/V
I2 = 30mA.
Therefore, the new current is 30miliAmps
If a new substance suddenly appears that wasn't there originally,
then a chemical change has occurred.
Like for example, (this is the only example I can think of right now):
-- You leave your bicycle outside in the rain, and it gets wet, and
a few days later there's some rust on it.
-- You scrape off some of the rust, take it to school, give it to the
Chemistry teacher, and ask her to analyze it and tell you what it
is. Later that day, she tells you it's a substance called "Iron oxide".
-- Where did that come from ? There was no iron oxide there.
There was only iron in the bicycle, and air, and water.
-- The iron oxide formed from a chemical change when the iron
on the surface of the bike combined with some of the oxygen in
the air, and molecules of a new substance were created. (For
some reason, the presence of water makes this chemical reaction
go faster.)
Answer:
∆v = 61.0 m/s
θ = 305°
Explanation:
Given;
initial velocity u= 50.0 m/s angle 270°
Final velocity v = 35.0 m/s angle 180°
∆v = v - u ........1
Resolving into x and y axis;
For y axis
∆vy = vsin180 - usin270
∆vy = 0 - (-50) = 50 m/s
x axis;
∆vx = vcos180 - ucos270
∆vx = -35 - 0= -35m/s
Magnitude of ∆v;
∆v = √(-35^2 + 50^2)
∆v = 61.0 m/s
Direction;
Tanθ = ∆vy/∆vx
θ = taninverse (50/-35)
θ = -55°
θ = 360-55 = 305°
False, rubber is a poor conductor but is a good insulator.
