Answer:
The act of using senses or tools to gather information is called <em>Obser</em><em>vation</em><em>.</em>
Answer:
What is the difference between the crust and lithosphere? The crust (whether continental or oceanic) is the thin layer of distinctive chemical composition overlying the ultramafic upper mantle. ... The lithosphere is the rigid outer layer of the Earth required by plate tectonic theory.
Explanation:
Hope this helps!
Answer:
Fnet = 0
Explanation:
- Since the block slides across the floor at constant speed, this means that it's not accelerated.
- According Newton's 2nd Law, if the acceleration is zero, the net force on the sliding mass must be zero.
- This means that there must be a friction force opposing to the horizontal component of the applied force, equal in magnitude to it:
- In the vertical direction, the block is not accelerated either, so the sum of the normal force and the vertical component of the applied force, must be equal in magnitude to the force of gravity on the block:
⇒ 169 N + Fn = Fg = 216 N (3)
- This means that there must be a normal force equal to the difference between Fappy and Fg, as follows:
- Fn = 216 N - 169 N = 47 N (4)
Answer:
The dose is 6 mSV
Explanation:
The absorbed dose (in gray - Gy) is the amount of energy that ionizing radiation deposits per unit mass of tissue. That is,
Absorbed dose = Energy deposited / Mass
while Dose equivalent (DE) (in Seivert -Sv) is given by
DE = Absorbed dose × RBE (Relative biological effectiveness)
First, we will determine the Absorbed dose
From the question, Energy deposited = 30mJ and Mass = 50kg
From,
Absorbed dose = Energy deposited / Mass
Absorbed dose = 30mJ/50kg
Absorbed dose = 0.6 mGy
Now, for the Dose equivalent (DE)
DE = Absorbed dose × RBE
From the question, RBE = 10
Hence,
DE = 0.6mGy × 10
DE = 6 mSv
-- Gravity makes a falling object fall 9.8 m/s faster every second.
-- So, it reaches the speed of 30 m/s in (30/9.8) = 3.06 seconds after it's dropped.
-- The distance an object falls from rest is D = 1/2 (acceleration) (time)²
D = 1/2 (9.8 m/s²) (3.06 sec)²
D = (4.9 m/s²) (9.37 sec²)
<em>D = 45.8 meters</em>
Notice that we don't care how high the building is. The problem works just as long as the object can reach 30 m/s before it hits the ground. That turns out to be anything higher than 45.8 meters for the drop . . . maybe something like 13 floors or more.
Now I'll go a little farther for you ! Writing the last paragraph made me a little curious and uncomfortable. So I went and looked up the world's tallest buildings . . . and I found out that this problem could never happen !
The tallest building in the world now is the Burj Khalifa, in Dubai. It has 163 floors, and it's 828 meters high ! That's 2,717 feet. It's gonna be a long time before there's a building that's 1125 meters tall, like this problem says. That's close to 3700 feet . . . I've had flying lessons where I wasn't that far off the ground !
