Answer:
16.5 kwh and 59400 kJ.
Explanation:
kWh is a measure of energy that is equivalent to the power in kw times the number of hours the device worked.
In this case, it would be equal to:
1 kw also means 1kj of energy spent per second. With this, we calculate the amount of energy in kJ spent by the resistance:
After looking at the transverse waves in the diagram you listed above, the one diagram that does represent the direction of particle X at the instant show in diagram number 3. The direction of the wave motion is up. The correct answer choice will be 3.
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.
When the ball starts its motion from the ground, its potential energy is zero, so all its mechanical energy is kinetic energy of the motion:
where m is the ball's mass and v its initial velocity, 20 m/s.
When the ball reaches its maximum height, h, its velocity is zero, so its mechanical energy is just gravitational potential energy:
for the law of conservation of energy, the initial mechanical energy must be equal to the final mechanical energy, so we have
From which we find the maximum height of the ball:
Therefore, the answer is
yes, the ball will reach the top of the tree.
B) The amount of work done
