Answer:

the answer is A.
Explanation:
Using the laws of newton:
∑F = ma
where ∑F is the sumatory of forces acting in the system, m the mass and a the acelertion of the system.
Then, if the block is moving with constant velocity, its aceleration is equal to 0, so:
∑F = m(0)
∑F = 0
It means that:
F -
= 0
where F is the force applied and
is the friction force. Replacing the value of F, we get:
310N -
= 0
Finally, solving for
:

Answer:
The box of rocks will have depression which can be seen without touching the box.
Explanation:
The density of rocks is very large as compared with napkins. So, the weight of the rocks will be much more greater than that of napkins.
As both boxes have same volume the heavier box will show depression on the lower surface as compared to the lighter box. So, the box of rocks will have depression which can be seen without touching the box.
Answer:
A. Light acts as particles, causing electrons on the surface it strikes to be destroyed.
Explanation:
- The photoelectric effect is a phenomenon that occurs when light shined onto a metal surface causes the ejection of electrons from that metal. It was observed that only certain frequencies of light are able to cause the ejection of electrons.
The <span>biogenous sediment contains the remains of dead organisms such as shells and skeletons.</span>
Answer: Acceleration due to gravity
Explanation: Force, F = mg, is a vector quantity because the acceleration due to gravity, g, is a vector quantity. Explanation: F = mg Where m is the mass (in kilograms) of the object in question and g is the acceleration due to gravity. Mass is a scalar quantity; mass has no dependence on direction whatsoever.