The net force is 6 N East
Explanation:
First of all, we start by noticing that all the forces act along the direction East-West, so we can simply find the net force by using algebraic addition.
In order to find the net force on the wheelchair, we need to define a positive direction and write down all the force with the proper sign.
Let's choose East as positive direction. Therefore, we have the following forces:
(east), the force applied by Ms. PB
(east), the force applied by Mr. Rigney
(west), the frictional force, acting in the opposite direction
(west), the air resistance, acting in the opposite direction
Taking into account the correct signs, we can now find the net force on the wheelchair:
And the positive sign tells us that the direction of the net force is East.
Learn more about forces:
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Answer:
532 millimeters of mercury
Explanation:
In order to convert the pressure from atm to millimeters of mercury (mm Hg), we should remind the conversion factor between the two units:
1 atm = 760 mm Hg
Therefore, we can solve the problem by setting up the following proportion:
Solving for x, we find
Answer:
Approximately 21 km.
Explanation:
Refer to the not-to-scale diagram attached. The circle is the cross-section of the sphere that goes through the center C. Draw a line that connects the top of the building (point B) and the camera on the robot (point D.) Consider: at how many points might the line intersects the outer rim of this circle? There are three possible cases:
There's only one such line that goes through the top of the building and intersects the outer rim of the circle only once. That line is a tangent to this circle. In other words, it is perpendicular to the radius of the circle at the point A where it touches the circle.
The camera needs to be on this tangent line when the building starts to disappear. To find the length of the arc that the robot has travelled, start by finding the angle which corresponds to this minor arc.
This angle comes can be split into two parts:
.
Also,
.
The radius of this circle is:
.
The lengths of segment DC, AC, BC can all be found:
In the two right triangles and
, the value of
and
can be found using the inverse cosine function:
.
The length of the minor arc will be:
.
