Democritus was the one who did not have experimental evidence to support his theory of the atom.
Answer: Option 4
<u>Explanation:
</u>
The discovery of atoms were first stated by Democritus but due to the absence of any experimental proof, his statement was not noted as significant at that time.
After this, Dalton made the specific assumptions formulating some postulates for the atomic theory with proof. Then the cathode rays tube experiments performed by Thomson lead to the formation of plum pudding models of atom.
This is followed by Rutherford’s gold foil experiment discovering the presence of nucleus inside the atoms. So, Democritus first stated but due to absence of experimental evidences, his theory of atoms were not supported at that time.
Answer:
F=ma is the relationship where, F is force, m is mass and a is acceleration.
Newton's second law states that the unbalanced force applied to the object accelerates the object which is directly proportional to the force and inversely to the mass.
If we apply force to a toy car then It will accelerate.
This is how Newton's second law of motion is verified.
Answer:
520 miles per hour
Explanation:
Let the speed of the Boeing 747 be x miles per hour.
The small airplane covers distance of 780 miles with speed 260 miles per hour.
Also,
After 1.5 hours the Boeing 747 leave the same place and reaches at same time. Both covered distance of 780 miles.
So,
<u>Time taken by Boeing 747 + 1.5 hours = Time taken by small plane.</u>
Also,
Time = Distance/ speed
So,
780 / x + 1.5 = 780/ 260
Solving for x, we get:
<u>x = 520 miles per hour</u>
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.
1 horsepower is equal to 746 W, so the power of the engine is
The power is also defined as the energy E per unit of time t:
Where the energy corresponds to the work done by the engine, which is
. Re-arranging the formula, we can calculate the time t needed to do this amount of work:
