Answer:C
Explanation:
Power=280watts=280/1000 kilowatts
Power=0.28 kilowatts
Device use 0.28 kilowatts in 1 day
1day=24hours
Device use 0.28 kilowatts in 24hours
30days=30 x 24=720 hours
For 720 hours=(0.28x720) ➗ 24
For 720 hours=201.6 ➗ 24
For 720 hours=8.4
Answer:
<u>Amplitude - remains the same</u>
<u>Frequency - increases</u>
<u>Period - decreases</u>
<u>Velocity - remains the same.</u>
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Explanation:
The amplitude of the wave remains the same since you are not changing the distance your hand moves and the amplitude of the wave depends on how much distance your hand covers while moving.
The frequency of your wave increases since now you are moving your hand more number of times in the same period i.e. your hand is moving faster in one second. So, the frequency of your wave increases.
The period is the time taken by the wave to travel a certain distance. Since your hand is now moving faster, the wave will travel faster and will take less time to cover the same distance hence, we can say that its period will decrease.
The velocity of a wave depends on the medium in which it is travelling. Your wave was previously travelling in air and the new wave is also travelling in the same medium so the velocity of the wave remains unchanged.

Explanation:
At the top of the tree, the velocity of the pebble is purely horizontal so we can calculate it as


negative acceleration- deceleration
Answer:
The variation and distribution of traits in a population depend on genetic and environmental factors. Genetic variation can result from mutations caused by environmental factors or errors in DNA replication, or from chromosomes swapping sections during meiosis.
Explanation:
Hope this helps!