Answer:
A new substance was formed
Explanation:
According to this question, a shiny and flexible metal called Magnesium (Mg) is burnt in air to produce a white powder that has no shiny or flexible properties, however, has more weight than the magnesium metal itself.
This is possible because a CHEMICAL CHANGE has occured, hence, a new substance has been formed. The formation of a new substance during the burning process (chemical reaction), induced the increase in mass.
Answer:
alcohol thermometers are used rather than Mercury thermometers in very cold regions because alcohol has a lower freezing point than Mercury.
Explanation:
To solve this problem we must apply the concept related to the longitudinal effort and the effort of the hoop. The effort of the hoop is given as
Here,
P = Pressure
d = Diameter
t = Thickness
At the same time the longitudinal stress is given as,
The letters have the same meaning as before.
Then he hoop stress would be,
And the longitudinal stress would be
The Mohr's circle is attached in a image to find the maximum shear stress, which is given as
Therefore the maximum shear stress in the pressure vessel when it is subjected to this pressure is 600Psi
Answer:
His machine must increase
Explanation:
If the ladder is vertical, then the work done in ascending equals his increase in potential energy.
For a man of mass (m) climbing height (h), the PE is (mgh), where g is the acceleration due to gravity.
If he does this in time t, his average power (rate of working) is:
mgh / t
= 80 * 9.81 * 6 / 12
= 392.4 W.
If the ladder is not vertical but inclined at an angle the horizontal, the power is mgh sin(a) / t.
