Answer:
C. Fill two identical pots with equal volumes of salt water and tap water and use a stopwatch to determine the time it takes each pot to boil.
Explanation:
<u>A) is incorrect</u> because Peter should have the same testing environment for both of his experiments.
He should choose the same method of boiling the salt water and tap water because the stovetop and the microwave could also affect the results and make them unreliable.
<u>B) is incorrect</u> because Peter should not estimate the time it takes the salt water and tap water to boil.
Peter should measure and record the amount of time that it takes these substances to boil in order to have an accurate, valid experimental thesis.
<u>C) is correct</u> because Peter uses the same volume of salt water and tap water, fills them into two identical pots, and uses a stopwatch to determine the amount of time it takes each pot to boil.
The stopwatch makes the experiment more valid and accurate compared to the previous methods, and the identical pots and amounts of water help this experiment become even more precise.
<u>D) is incorrect</u> because the variables in the experiment are not controlled amounts and will therefore produce an inaccurate and invalid experiment.
Answer:
An object on the moon would weigh the LEAST among these. So correct answer is B.
Explanation:
- Weight of an object on any place is given by:
W = Mass * Acceleration due to gravity(g)
- It means when masses of different objects those are in different places are same, the weight of those objects depends upon the 'g' of that particular place.
- As we know, acceleration due to gravity on surface of moon (g') is 6 times weaker than the acceleration on surface of earth (g), which is due to the large M/R^2 of the earth than the moon.
i.e. g' = g/6 so W' = W/6
- And in the space between the two, the object is weightless.
Answer:
Gravitational Potential Energy
Explanation:
As an object falls from rest, its gravitational potential energy is converted to kinetic energy. Conservation of energy as a tool permits the calculation of the velocity just before it hits the surface.
The answer is D. Electrical energy can be transformed into both heat and light.
