<span>The relative hardness of a mineral can be tested by the Moh’s scale or the mineral hardness. The Moh’s scale can be characterized by the ability of the mineral to resist scratch resistance by scratching a harder or softer mineral. It has a scale of 1 to 10 where 1 being the softest and 10 being the hardest. The relative hardness of a mineral can best be tested by scratching the mineral across a glass plate. The answer is letter A. </span>

6 0

3 years ago

What is the momentum of a 0.5 kg ball which is thrown at 20 m/s?

tatuchka [14]

A =-16.7 Ns B= -167.N

7 0

3 years ago

Ryan swings a pail of water in a vertical circle 1.0 m in radius at a constant speed. If the water is NOT to spill on him:

nexus9112 [7]

Part 1

If water does not spill at the top point of the circular motion then for the minimum speed condition we can say normal force will be zero at the top position

$F_g = ma$

$mg = m\frac{v^2}{R}$

$g = \frac{v^2}{R}$

$v = \sqrt{Rg}$

given that

R = 1 m

g = 9.8 m/s^2

now from above equation we have

$v = \sqrt{1(9.8)} = 3.13 m/s$

Part b)

for minimum value of angular speed we will have

$\omega = \frac{v}{R}$

$\omega = \frac{3.13}{1}$

$\omega = 3.13 rad/s$

3 0

3 years ago

Each of the four expansion models (recollapsing, critical, coasting, and accelerating) predict different ages for the universe,

cupoosta [38]

Answer:

This is because the age of the universe is determined by the pace of expansion in the past, and each model forecasts a different pace.

Explanation:

The age of the universe is determined by the pace of expansion in the past, and each model forecasts a different pace.

This is due to the fact that the expansion rate in the coasting model is constant and never changes. Because the cosmos is growing faster now than during the old days, recollapsing and critical models give shorter ages. According to the accelerating model, the universe is growing at a slower rate currently than in the past, implying an older age.

4 0

3 years ago