Answer:
10.2 kg
Explanation:
Assuming the object is on Earth:
w = mg
m = w / g = 100 / 9.81 = 10.2kg
Answer:
(a) 
(b) 
Explanation:
According to the law of conservation of momentum:

Initially, the girl and the plank are at rest. So, relative to the ice, we have:

(a) The velocity of the girl relative to the ice is:

Here,
is the velocity of the girl relative to the plank and
is the velocity of the plank relative to the ice.
Replacing (1) in (2):

(b) According to (2), the velocity of the plank relative to the surface of ice is:

The negative sing indicates that the plank is moving to the left.
Answer:
The absolute pressure of air inside the tank is 164.7 psi.
Explanation:
Given that,
Atmospheric pressure = 14.7 Psi
Gauge pressure = 150 psi
We need to calculate the absolute pressure of air inside the tank
Using formula of absolute pressure

Where,
= gauge pressure
=atmospheric pressure
Put the value into the formula


Hence, The absolute pressure of air inside the tank is 164.7 psi.
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