d. natural gas is the answer
Well,
A control in an experiment would basically be the "normal" version of your test subjects.
In a drug testing experiment with people, the control group would be the people who don't take the drug.
In an experiment on the effects of salt on potatoes, the control group would be a potato without salt on it.
So in an experiment to measure the effects of gas additives on fuel, the control would be fuel without additives.
Answer:
9 cm.
Explanation:
The energy used for stretch the spring from
to
will be ,
The energy used for stretch the spring from
to
will be ,
using the energy of spring formula ,we find that


Dividing both the equation will get,

Therefore, the natural length of the spring is, 9 cm.
Answer:
current in series is 2.50 mA
current in parallel is 13.51 mA
Explanation:
given data
voltage = 5 V
resistors R1 = 1.5 kilo ohms
resistors R2 = 0.5 kilo ohms
to given data
current flow
solution
current flow in series is express as here
current = voltage / resistor .................1
put here all value in equation 1
current = 5 / (1.5 + 0.5)
current = 5 / 2.0
so current = 2.50 mA
and
current flow in parallel is express as
current = voltage / resistor ....................2
put here all value in equation 2
current = 5 / (1/ (1/1.5 + 1/0.5))
current = 5 / 0.37
so current = 13.31 mA