<span>B. because they cannot make light rays converge</span>
A boiling pot of water (the water travels in a current throughout the pot), a hot air balloon (hot air rises, making the balloon rise) , and cup of a steaming, hot liquid (hot air rises, creating steam) are all situations where convection occurs.
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Answer:
D. 1.8 × 102 newtons radially inward
Explanation:
The magnitude of the centripetal force is given by:

where
m is the mass of the object
v is the tangential speed
r is the radius of the circular trajector
In this problem, we have m = 4.0 kg, v = 6.0 m/s and r = 0.80 m, therefore substituting into the equation we get

The centripetal force is the force that keeps the object in a circular trajectory, so it is a force that is always directed inward (towards the centre of the circular path) and radially. Therefore, the correct answer is
D. 1.8 × 102 newtons radially inward
Since the tower base is square with a side length of 125 m,
Therefore,

Square root of 31250 = 176.776953 (Diameter)
, so this is the diameter of the cylinder to enclose it, and radius, r = 88.38834765 m and height, h = 324 m.
The volume of cylinder,

Thus, the mass of the air in the cylinder,

Hence, the mass of the air in the cylinder is this more than the mass of the tower.
The force constant of the spring is determined as 14,222.2 N/m.
<h3>Force constant of the spring</h3>
Apply the principle of conservation of energy,
K.E = U
where;
- K.E kinetic energy of the elevator
- U is elastic potential energy of the spring
¹/₂mv² = ¹/₂kx²
mv² = kx²
k = mv²/x²
Where;
- m is mass of the elevator
- v is speed
- x is compression of the spring
k = (2000 x 8²)/(3²)
k = 14,222.2 N/m
Thus, the force constant of the spring is determined as 14,222.2 N/m.
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