In case of an object sitting at rest on another base, there are two equal and opposite forces – Normal force and the gravity.
Answer: Option A
<u>Explanation:
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When an object is placed at rest position on another object, there is a force exerted by the surfaces of the two contact objects. This force is denoted as Normal Force.
When an object such as a box is placed on a shelf, its surface exerts a contact force on the base of the shelf- The Normal force directed upward. Meanwhile, the gravity stays at its action and tries to pull the box towards itself.
Both of these forces however are equal and opposite and therefore, there is zero net force on the box. That's why it remains at rest, holding on Newton's third law.
Answer:
This difference is kept to a minimum because the resistance in transformers is a few tens of ohms and the resistance of modern voltmeters is of the order of MΩ.
Explanation:
A voltmeter is built by a galvanometer and a resistance in series, this set is connected in parallel to the resistance where the voltage is to be measured, therefore the voltage is divided between the voltmeter and the element to be measured, consequently the measured voltage It is less than the calculated one, since for them the resistance of the voltmeter is assumed infinite.
This difference is kept to a minimum because the resistance in transformers is a few tens of ohms and the resistance of modern voltmeters is of the order of MΩ.
Answer:
The set of frequencies of the electromagnetic Waves emitted by the atoms of an element is called emission spectrum.
D. Power. The unit of power is watt.
Answer:
The length at the final temperature is 11.7 cm.
Explanation:
We need to use the thermal expansion equation:
Where:
- L(0) is the initial length
- ΔT is the differential temperature, final temperature minus initial temperature (T(f)-T(0))
- ΔL is the final length minus the initial length (L(f)-L(0))
- α is the coefficient of linear expantion of steel (12.5*10⁻⁶ 1/°C)
So, we have:
Therefore, the length at the final temperature is 11.7 cm.
I hope it helps you!
