Answer:
Options B, A, D, C
Explanation:
When a scientists, let's say Roberto wonders if the presence of other elements also affects the color of a flame, he can decide to prove this through a study. Therefore, in chemistry class, Roberto sees that traces of lithium makes a flame appear bright red. Subsequently, Roberto designs an experiment to test flame color in the presence of different elements and finally Roberto's friend tells him the color of a flame cannot be changed, but Roberto is still unsure.
The letter i is used to signify that a number is an imaginary number. It stand for the square root of negative one.
Answer:
Hypotheses must be testable, and once tested, they can be supported by evidence. If a statement is made that cannot be tested and disproved, then it is not a hypothesis.
Answer:
R= 5.4 ohms
Explanation:
Given that
V= 9 V
Power ,P= 15 W
Lets take resistor resistance = R
We know that Power given as

V=Voltage
P=Power
R=Resistance

Now by putting the all the values in the above equation

R= 5.4 ohms
Therefore the resistance of the resister will be 5.4 ohms.
The time taken by the ballast bag to reach the ground is 2.18 s
The ballast bag at rest with respect to the balloon has the upward velocity (u) of 4.6 m/s , which is the velocity of the balloon. When it is dropped from the balloon, its motion is similar to an object thrown upwards with an initial velocity <em>u </em>and it falls under the acceleration due to gravity<em> g.</em>
Taking the upward direction as positive and the downward direction as negative, the following equation of motion may be used.

The bag makes a net displacement <em>s</em> of 13.4 m downwards, hence

Its initial velocity is

The acceleration due to gravity acts downwards and hence it is negative.

Use the values in the equation of motion and write an equation for t.

Solving the equation for t and taking only the positive value for t,
t=2.18 s