Answer:
b)
Explanation:
Normal force, is always directed upward the surface over which is placed the object, and can adopt any value, as required to meet Newton's 2nd Law.
In this case, as the external force on the suitcase pulls upward, in order to counteract the influence of gravity, normal force is less than the weight of the suitcase, as follows:
F + Fn = m*g
⇒ Fn = m*g - F
So, the normal force is equal to the magnitude of the weight of the suitcase (m*g) minus the magnitude of the force of the pull (F) which is the same expressed by the statement b.
Answer:
7 miles southwest
9 steps to the left
75 mph north
Explanation:
A vector quantity is any physical quantity that specifies the magnitude of the quantity and its direction.
So, the choices that gives a magnitude and direction are vectors.
The other type of physical quantities are the scalar which only specifies the magnitude but no direction;
9 steps to the left and 7 miles southwest are called displacement
75 mph north is velocity
Answer:
Q = 675 [J]
Explanation:
We can calculate the amount of heat transfer by means of the following expression that includes the mass and temperature change in a body as a function of the specific heat.
where:
m = mass = 25 [gr]
Cp = specific heat = 0.9 [J/g*°C]
Tinitial = 55 [°C]
Tfinal = 25 [°C]
![Q=25*0.9*(55-25)\\Q=675 [J]](https://tex.z-dn.net/?f=Q%3D25%2A0.9%2A%2855-25%29%5C%5CQ%3D675%20%5BJ%5D)
Answer:
D. The liquid has absorbed as much heat as it can until it starts to vaporize.
I don't like any of those choices. But if you absolutely have to pick your answer
from this list, then it has to be 'D'.
The ocean is an enormous storage vessel for heat. It gets heat from the air in
the Summer ... which somewhat cools places near the coast ... and it releases
heat into the air during the Winter ... which warms places near the coast.
So I guess it's true that ocean surfaces change temperature more slowly than
land surfaces do, and they influence the land nearby in the process. But this
ignores the reason for the slow changes in ocean surface temperature. It's a
lot like saying that the loud noise produced by a race car is the result of the
car's ability to appear in a far different location after a short time.
