The correct answer is
<span>c. one person exerts more force than the other so that the forces are unbalanced.
In fact, the door is initially at rest. In order to move the door, a net force different from zero should be applied, according to Newton's second law:
</span>

<span>where the term on the left is the resultant of the forces acting on the door, m is the door mass and a its acceleration.
In order to move the door, the acceleration must be different from zero. But this means that the resultant of the forces acting on it must be different from zero: this is possible only if the forces applied by the two persons are unbalanced, i.e. one person exerts more force than the other.</span>
Answer:
Explanation:
Often times, the property of air masses is a function of where they originate from especially with respect to latitude.
An air mass is certain amount of air with some unique set of temperature and vapor component.
- Air masses differs from places to places based on where they originate.
- Continental air masses are usually dry and cold because there is little to no water on a land mass.
- Air masses that originates from the surface of the ocean are predominantly moist.
- In polar regions, the air mass is cold.
- Around the tropics, they are usually warm due to insolation here.
We are given the following:
Bobo's swimming speed = 2.0 m/s
Width of the river = 100 m
Flowrate of the river = 6.0 m/s due east
First, we need to illustrate the problem. Draw the river with a width of 100 meters. Then, the flow of the river, east at 6 meters per second. Lastly, draw Bobo at one side of the river facing north and an arrow representing swimming speed at 2 meters per second.
Now, we can use the Pythagorean theorem to solve this rate problem.
c^2 = a^2 + b^2
c = speed of Bobo needed
a = speed of Bobo facing north
b = flow rate of the river going east
c^2 = 2^2 + 6^2
c = 6.32 m / s should be his speed to overcome the current and make a landing at the desired location.