Answer:
D. are brought from the mantle to the surface in magma that hardens into komatiite.
Explanation:
Diamond :
It is the hardest form of carbon.The atomic atoms arrange in the cubic crystal structure and this is known as diamond cubic.Another form of the diamond at room temperature is graphite.This is used for making jewelry.This is also used in the cutting process because it has high strength.
Therefore the correct option for the diamond is D.
Answer:
8 time increase in K.E.
Explanation:
Consider Mass of truck = m kg and speed = v m/s then
K.E. = 1/2 ×mv²
If mass and speed both are doubled i.e let m₀ = 2m and v₀ = 2v then
(K.E.)₀ = 1/2 ×2m(2v)²
(K.E.)₀ = 8 (1/2 × mv²) = 8 × K.E.
Answer:

Explanation:
Given that,
The elevator is moving up and slowing down at the rate of, 
The acceleration due to gravity, 
Mass of the person, m = 93.3 kg
To find,
The reading of the scale.
Solution,
As the elevator is moving down with some acceleration. The net force acting on it is given by :




So, the scale will read 1194.24 N.
Answer:
Explanation:
Conservation of momentum is used to solve
Unfortunately we have a missing piece of information such as the initial velocity of the unknown mass train.
If we ASSUME that the second train is at rest
5000(100) + m(0) = 5000(50) + m(50)
which means m = 5000 kg
However, I'll show you the importance of knowing that initial velocity by finding it assuming the other answers are valid
if m = 15000 kg
5000(100) + 15000(v₀) = (5000 + 15000)(50)
v₀ = 33 ⅓ m/s
if m = 10000 kg
5000(100) + 10000(v₀) = (5000 + 10000)(50)
v₀ = 25 m/s
if m = 8000 kg
5000(100) + 8000(v₀) = (5000 + 8000)(50)
v₀ = 18.75 m/s
So you can see why I had to assume an initial velocity. Any of the masses could work if the initial velocity is chosen correctly.