<u>Note that</u>:
The gravitational potential energy =
where m: is the mass, g: the acceleration due to the gravity and h is the height from the earth surface
Then, we can increase the gravitational potential energy by increasing the mass or the height from the earth surface
<u>In our question</u>, we can increase the gravitational potential energy by
<u>A) Strap a boulder to the car so that it wights more.</u>
Answer:
<u>6 bulbs</u> are needed to illuminate the room.
Explanation:
Given:
Measurement of kitchen (A) = 10 ft by 10 ft = 100 sq. ft
Number of footcandles (n) = 50
Lumens emitted by 1 bulb = 834
Number of bulbs (N) = ?
We are also given,
1 foot candle = 1 lumen/sq. ft
So, 50 foot candles = 50 lumens/sq. ft
Now, for an area of 1 sq. ft 50 lumens are emitted.
So, for an area of 100 sq. ft, lumens emitted = 50 × 100 = 5000 lumens
Now, one bulb emits = 834 lumes
Therefore, number of bulbs required for emitting 5000 lumens is given as:
So, 6 bulbs are needed to illuminate the room.
Here we have to calculate the number of rotations made by earth around its own axis in the entire life time of a human being.
The average human life is 50 years .
Each year is 365.5 days
Hence
=18,275 days
The earth rotates around its own axis in 23 hours 56 minutes and 4 second which is approximately equal to 24 hours or one days.
Hence one rotation takes one days.
⇒18,275 days =18,275 rotations
Hence the total number of rotations made by earth around its own axis in the life time of a average human life time will be 18,275 times