Answer:

Explanation:
Given;
The operational pressure of the cooker, 
area of the opening, 
- We know that the gauge pressure is measured with respect to the atmospheric pressure. As the atmospheric pressure acts on all the components of the system being observed so, we only need to counter the gauge pressure.
As the petcock sits on the opening of the cross-section so, it balances the built-in pressure due to its weight.
<u>Hence:</u>

where:
mass of the petcock
acceleration due to gravity


Answer:
2800000J
Explanation:
Parameters given:
Mass = 920kg, weight = 920 * 9.8 = 9016N
Distance = 310m
Angle of inclination = 6.5°
Work done is given as :
W = F*d*cosA
Where A = angle of inclination
W = (9016 * 310 * cos6.5)
W = 2776993.59J
In 2 significant figures, W = 2800000J
Answer: The ends of a magnet are called the poles. Each magnet has a north pole and south pole.

Answer:
Explanation:
Given
mass of cannon and cart is 
Spring constant 
mass of Projectile 
Launch Velocity of cannon 
Launch angle 
As the External Force is zero therefore we can conserve momentum
Initially both Projectile and cannon is at rest
Conserving momentum in horizontal direction




i.e. cannon is moving in opposite direction of Projectile