i'm stuck on that question also
Answer:
<u>Question 2</u>
<u>Part (a)</u>
Chlorine: type of compound = chloride
Oxygen: type of compound = oxide
<u>Part (b)</u>
The iron reacts with water and oxygen to form rust.
A water molecule is made up of two hydrogen atoms joined to one oxygen atom: Di-hydrogen oxide.
<u>Question 3</u>
This circuit is in parallel.
The current in a parallel circuit splits into different branches then combines again before it goes back into the supply.
We are told that A₁ = 0.8 A
As the lamps have <u>equal resistance</u>, the current splits equally:
A₂ = 0.4 A
A₃ = 0.4 A
Then combines again:
A₄ = 0.8 A
Input heat, Qin = 4 x 10⁵ J
Output heat, Qout = 3.5 x 10⁵ J
From the first Law of thermodynamics, obtain useful work performed as
W = Qin - Qout
= 0.5 x 10⁵ J
By definition, the efficiency is
η = W/Qin
= 100*(0.5 x 10⁵/4 x 10⁵)
= 12.5%
Answer: The efficiency is 12.5%
Let the distance between the towns be d and the speed of the air be s.
distance = speed * time
convert the minutes time into hours.
When flying into the wind, ground speed will be air speed MINUS wind speed, hence the against the wind trip is described by:
d
s−15
=
7
3
return trip is then :
d
s+15
=
7
5
Cross-multiplying both we get the two-variable system:
3d=7∗(s−15)5d=7∗(s+15)
3d=7s−1055d=7s+105
subtract first equation from second equation we get
2d=210d=105km
Substitute the value of d in the above equations for s.
5∗105=7s+1057s=420s=60km/hr
A fuse melts to protect a circuit.
