The initial temperature of the bar is 25. To get to the t temperature you need to add (t-25) degrees Celsius.
for 1 degree................... 7 Joules
y given degree........ p Joules
p=7y
In our case y=(t-25) .
h(t) = 7(t-25) which is the final answer.
Answer:
c) 
Explanation:
Coulomb's law says that the force exerted between two charges is inversely proportional to the square of distance between them, and is given by the expression:

where k is a proportionality constant with the value 
In this case
, so we have:

Solving the equation for q, we have:



Replacing the given values:


Answer:
Re=160ohm
Explanation:
Step#1
Rt=R1+R2 ( because both are in series)
Rt=(100+220 ) ohm
Rt=320 ohm
Step#2
Rt and R3 are parallel so,
Re= (Rt× R3) ÷ (Rt+R3)
Re= (320×320)÷( 320+320)
Re = 102,400÷ 640
Re=160ohm
Answer : 5m/s
Explanation:the formular for velocity is distance /time or you can say displacement /time. Then it would then be
100/20 =5m/s