<u>Answer</u>
3 Ohms
<u>Explanation</u>
when the resistors are in series, the resistance in the circuit increases. For example, if two resistors, R1 and R2 are in series, the combined resistance is R1+R2.
When connected in parallel, the total resistance is the reciprocal of (1/R1 + 1/R2)
In this case the resistors are in parallel.
Total resistance = (1/12 + 1/4)⁻¹
= (1/3)⁻¹
= 3 Ohms
Answer:
It is equal to the overall momentum before collision, so far no external object is involved.
Explanation:
Momentum is always conserved during collision as a rule. This is equal to the product of the mass and velocity. Thank you.
Explanation:
First we will convert the given mass from lb to kg as follows.
157 lb = 
= 71.215 kg
Now, mass of caffeine required for a person of that mass at the LD50 is as follows.

= 12818.7 mg
Convert the % of (w/w) into % (w/v) as follows.
0.65% (w/w) = 
= 
= 
Therefore, calculate the volume which contains the amount of caffeine as follows.
12818.7 mg = 12.8187 g = 
= 1972 ml
Thus, we can conclude that 1972 ml of the drink would be required to reach an LD50 of 180 mg/kg body mass if the person weighed 157 lb.