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:
</u>
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:
18600j
Explanation:
It is given that,
Number of moles = 3
Temperature, T = 25°C = 25+273 = 298 K
The internal energy of N₂ gas is given by :
U=f\times nRTU=f×nRT
f is degrees of freedom. For diatomic gas, degree of freedom is equal to 5/2. So,
\begin{gathered}U=\dfrac{5}{2}\times 3\times 8.31\times 298\\\\U=18572.85\ J\end{gathered}
U=
2
5×3×8.31×298
U=18572.85 J
or
U = 18600 J
So, the internal energy of the gas is 18,600 J
The initial kinetic energy of the boat and its rider is
After Sam stops it, the final kinetic energy of the boat+rider is
because its final velocity is zero.
For the law of conservation of energy, the work done by Sam is the variation of kinetic energy of the system:
where the negative sign is due to the fact that the force Sam is applying goes against the direction of motion of the boat.
Answer: c. Generally, metals are ductile.
Explanation:
From the options given in the question, the correct statement is that"Generally, metals are ductile.
Ductility of a metal simply means that a metal can be plastically deform before it is then fractured. It implies that metals can be drawn to thin wires. The only exception we have in this case is mercury.
1) 0N... friction opposes the motion of an object, since the block is at rest there is no motion thus no friction
2) F=ma
= (5.5kg)(30m/s)
=165 N
