Well, I'll try to write the formula in a way that's not confusing,
but I'm afraid it might be slightly confusing anyway.
When you're working with dB, the basic rule is
A change of 10 dB means either multiplying or dividing by 10 .
Multiply something by 10 ==> it increases by 10 dB.
Divide something by 10 ==> it decreases by 10 dB.
It turns out that another way to write all of this is . . .
An increase of 10 dB ===> multiply the original amount by 10¹
An increase of 20 dB ===> multiply the original amount by 10²
An increase of, say, 7 dB ===> multiply the original amount by 10⁰·⁷
A decrease of 10 dB ===> multiply the original amount by 10⁻¹
A decrease of 30 dB ===> multiply the original amount by 10⁻³
A decrease of, say, 13 dB ===> multiply the original amount by 10⁻¹·³
This question says: The sound increases by 5 dB .
That means the original 'intensity' or 'power' of the sound
is multiplied by
10⁰·⁵ = √10 = about 3.162 (rounded) .
From the choices listed, the closest one is (c).
Addition of 2vector gives you 1large vector quantity
Answer:
7056 kJ
Explanation:
Given that,
Mass of a ship roller coaster is 36,000 kg.
It reaches a height of 20 m off the ground
We need to find the gravitational potential energy does it have. The formula for the gravitational potential energy ios given by :
E = mgh
g is acceleration due to gravity
E = 36,000 kg × 9.8 m/s² × 20 m
= 7056000 J
or
E = 7056 kJ
So, it will have 7056 kJ of gravitational potential energy.
Answer:
8) 1500 feet
9) 20 miles
10) 4 Days
11) 2250 miles
12) 1 hour and 5 minutes
13) 27.27miles per hour
Explanation
8) There are 60 seconds in one minute so 60x25=1500 feet
9) 30 minutes is half of an hour so 40 miles ÷ 2 = 20 miles
10) 12x4=48
11) 500 miles x 4.5 hours is 2250 miles
12) Train leaves at 3pm after 60 miles it will be 4 pm and after 5 more miles 4:05 pm so 1 hour and 5 minutes
13)
Elmo = 40 minutes and 5 miles
Bert and Ernie = 45 minutes and 15 miles
Cookie Monster = 20 minutes and 10 miles
Home = 5 minutes abd 20 miles
Average Speed including stops is 27.27 miles per hour
Correct answer choice is:
D. A frequency higher than the original frequency.
Explanation:
This is a true case of Doppler's effect. The Doppler effect can be defined as the effect originated by a traveling source of waves in which there is a visible higher variation in pulse for observers towards what the source is progressing and a visible descending shift in rate for observers from what the source is dropping.
