Answer:
A) and B) are correct.
Explanation:
If the object is at rest, it means that no net force is exerted on it.
As the object experiences a downward gravitational force from Earth, in order to be at rest, it must experience an upward force with the same magnitude as the gravitational force on the object.
This force is supplied by the normal force, which can adopt any value in order to meet the condition imposed by Newton´s 2nd Law, and is always perpendicular to the surface on which the object is placed (in this case, the ground).
At a molecular level, this normal force is supplied by the bonded molecules of the ground that behave like small springs being compressed by the molecules of the object, exerting an upward restoring force upward on them.
So, the statements A) and B) are true.
The diagram represents a chain reaction that is caused by nuclear fission.
<h3>What is a nuclear fission reaction?</h3>
A nuclear fission reaction is a reaction in which the nucleus of a larger atom is split into two or more smaller nucleus of atoms.
Nuclear fission can proceed in the form of a chain reaction in which the products of the first fission reaction are used to initiate further fission reactions.
Therefore, the diagram represents a chain reaction that is caused by nuclear fission.
Learn more about nuclear fission at: brainly.com/question/22155336
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Answer:
T = 692.42 N
Explanation:
Given that,
Mass of hammer, m = 8.71 kg
Length of the chain to which an athlete whirls the hammer, r = 1.5 m
The angular sped of the hammer,
We need to find the tension in the chain. The tension acting in the chain is balanced by the required centripetal force. It is given by the formula as follows :
So, the tension in the chain is 692.42 N.