52 items are filed under this topic.
 |
 |
 |
 |
 |
 |
 |
 |
|
Two line segments in the plane |
2011-08-15 |
 |
From Tim: For this problem I actually have tried to visualise the image in my head many times. This question makes my head spin.
Four points lie in a plane. They are partitioned into two pairs so that the sum of the lengths of the segments joining the points of each pair has the minimal possible value.
Prove that these segments have no common points. Answered by Chris Fisher. |
 |
 |
 |
 |
 |
|
Points with distance 5 from the point (-2, -1) |
2011-01-19 |
 |
From Alexa: Find all points having a x-coordinate of 2 whose distance from the point (-2, -1) is 5. Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
The angle between a line and a plane |
2011-01-12 |
 |
From tom: what are the angles of the diagonal of a rectangular parallelepiped 2in by 3 in by 4 in
makes with the faces...
You know this is a problem that I can't figure out ...I don't know where
the angle and the diagonals where? can you help me with this one? Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
What is its speed in still air? |
2010-11-28 |
 |
From Shelby: An Airplane flies a certain distance in 3 hours going WITH a 40km/hr wind. It travels the same distance in 5 hours when going against the wind. What is it's speed and how long would it take to travel the same distance in still air? Distance = speed x time Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
Two jets leave denver at 9 am. |
2010-10-15 |
 |
From Carl: two jets leave denver at 9 am. One flying east at a speed of 50 km per hour greater than the other which is traveling west. At 11 am the planes are 2500 km apart. Find their speeds. Answered by Stephen La Rocque. |
 |
 |
 |
 |
 |
|
Graphical Representation of Complex Numbers |
2010-06-08 |
 |
From Anas: why do we write complex number a+ib as (a,b)? Answered by Janice Cotcher. |
 |
 |
 |
 |
 |
|
Can a line segment curve over two planes? |
2010-02-14 |
 |
From Graham: I am working on a math fair project.
Can a line segment curve over two planes?
Such as, if I had a three dimensional L bracket and I drew a line segment
on it with a marker starting on the bottom of the L and had it curve
around the corner and up the top, would it still be considered one line
segment? Or is that two line segments?
Is there a rule that a line segment can only occupy one plane?
Thank you.
Graham Answered by Chris Fisher. |
 |
 |
 |
 |
 |
|
Two jets are traveling towards each other |
2009-10-05 |
 |
From jake: two jets are traveling towards each other and are 4000 km apart. the rate of one jet is 100 km/h faster than the rate of the other. if the jets pass each other after 2.5 hrs what is the rate of speed of the faster jet? Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
At what speed does an automobile start to hydroplane? |
2009-06-03 |
 |
From Don: How do you figure at what speed does an automobile start to hydroplane when driving on a wet surface. Answered by Robert Dawson. |
 |
 |
 |
 |
 |
|
An aeroplane flying in a wind |
2009-06-02 |
 |
From Maria: The aeroplane flies in a wind of speed 50 kph from the direction S80◦W. However, the direction in which it is pointed, and its speed in still air,
are such that its resultant speed and direction are 800 kph, and direction N71.6◦E
I need to find the size of the angle between v and vw, in degrees to one
decimal place, and find the speed at which the aeroplane would fly if the air were
still, to the nearest kph.
It would help me greatly if I could see a diagram illustrating the velocity va that the aeroplane
would have if the air were still, the velocity vw of the wind, and
the resultant velocity v of the aeroplane (diagram should be
in the form of a triangle illustrating how one velocity vector is the
sum of the other two)
Thanks Answered by Harley Weston. |
 |
 |
 |
 |
 |
|
A plane cuts a line segment |
2009-03-17 |
 |
From Manis: Find the ratio in which the line joining (2,4,16) and (3,5,-4) is divided by the plane 2x-3y+z+6=0. Answered by Robert Dawson. |
 |
 |
 |
 |
 |
|
A slopped table top |
2009-03-16 |
 |
From anthony: A perfect circle with radius 100m is supported by four legs, 50m long. The circle is flat when all four legs are 50m long, and tilted when the legs are different in length. The four legs are spread evenly 90 degrees apart at 0, 90, 180, and 270. Find the high and low points in degree and height when the legs are 55m at 0 degree, 70m at 90 degree, 45m at 180 degree, and 30m at 270 degree.
Not sure if they can be calculated using only 2 or 3 legs.
I have tried by picking the two adjacent highest legs (55m and 70m) so I know the high point falls into the first quadrant. Then I tried using ratio to determine where the high point is, which I think high point should be closer to the 70m leg, I am not sure. If I can find the high point, the low point should be opposite to it. Answered by Chris Fisher and Harley Weston. |
 |
 |
 |
 |
 |
|
Related rates |
2009-03-09 |
 |
From Megan: A plane flying with a constant speed of 330 km/h passes over a ground radar station at an altitude of 3 km and climbs at an angle of 30°. At what rate is the distance from the plane to the radar station increasing a minute later? Answered by Harley Weston. |
 |
 |
 |
 |
 |
|
How fast is the visible surface of the earth decreasing? |
2009-01-24 |
 |
From Ray: A dive bomber loss altitude at a rate of 400 mph. How fast is the visible surface of the earth decreasing when the bomber is one mile high? Answered by Harley Weston. |
 |
 |
 |
 |
 |
|
How far is the airplane from the control tower? |
2009-01-17 |
 |
From Murtaza: An aircraft is vertically above a point which is 10 km west and 15 km north of a control tower. The aircraft is 4000 m above the ground, how far is it from the control tower? Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
The area of a region in the plane |
2009-01-03 |
 |
From Rogerson: Find the area, S, of the shaded region enclosed by the given cureve, the given line and the x-axis.
y = -x^2 + 1
line x = 2 Answered by Harley Weston. |
 |
 |
 |
 |
 |
|
What is i^i? |
2008-12-27 |
 |
From randomness: i have learnt that 'i' is square root of -1. What is then i^i ? It baffles my maths teacher... Answered by Robert Dawson and Penny Nom. |
 |
 |
 |
 |
 |
|
How fast is the distance between the airplanes decreasing? |
2008-11-10 |
 |
From Crystal: At a certain instant, airplane A is flying a level course at 500 mph. At the same time, airplane B is straight above airplane A and flying at the rate of 700 mph. On a course that intercepts A's course at a point C that is 4 miles from B and 2 miles from A. At the instant in question, how fast is the distance between the airplanes decreasing? Answered by Harley Weston. |
 |
 |
 |
 |
 |
|
The flight of an airplane |
2008-08-29 |
 |
From kobina: You are traveling on an airplane that is moving at 500 mph in a direction 40deg north of west.Therefore , You are travelling (due to the plane ) at how many mph toward the west. Answered by Stephen La Rocque. |
 |
 |
 |
 |
 |
|
What is the altitude of the plane? |
2008-04-23 |
 |
From tiana: If a plane is taking off and its climbing at 380 feet per minute at 205 MPH, what is the altitude of the plane after it traveled 115 miles? Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
A package of supplies is dropped from a plane |
2008-02-29 |
 |
From beth: An airplane flies west at a speed of 200m/s. A package of supplies is dropped from the plane to some campers. if the plane is at an altitude of 1000meters, how far from the campers should the package be dropped to land near them? ignore wind resistance. Answered by Stephen La Rocque. |
 |
 |
 |
 |
 |
|
Forces on an inclined plane |
2008-01-10 |
 |
From Ron: A body that weighs 540lbs is caused to slide up an inclined plane with a uniform velocity by a force that acts parallel to the plane. For each foot of horizontal distance, there is a vertical rise of 2in. If the coefficient of sliding friction is 0.16, what force is required to move the body? Answered by Stephen La Rocque. |
 |
 |
 |
 |
 |
|
The radius of a planet |
2008-01-06 |
 |
From Ben: Two people who are both h feet tall are standing on a spherical planet. One person walks a distance d in feet away from the the other person. At this point, the person walking turns around and can no longer see the top of the other persons head. What is the radius of the planet? Answered by Stephen La Rocque and Harley Weston. |
 |
 |
 |
 |
 |
|
What is the speed of the plane in still air? |
2008-01-05 |
 |
From oscar: A plane flies 400 miles with the wind and 340 miles against the wind
in the same length of time. If the speed of the wind is 24mph, what is
the speed of the plane in still air? Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
Points that are 15 units from the origin |
2007-09-20 |
 |
From Paula: Find the coordinates of any point(s) 15 units away from the origin with an
x-coordinate of 9.
I was given the answer: (9,12) and (9,-12), but I do not understand how these numbers
were calculated. Thank you for your help! Answered by Stephen La Rocque. |
 |
 |
 |
 |
 |
|
Points in a plane |
2007-06-01 |
 |
From Gabrielle: In general how many planes are there which contain two given points, three given points, and four given points? Answered by Steve La Rocque and Walter Whiteley. |
 |
 |
 |
 |
 |
|
The intersection of two planes |
2007-05-31 |
 |
From Sarim: How to find a intersection of two planes? Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
The velocity of an aircraft |
2007-03-22 |
 |
From William: Hello,
I don't understand how to work this problem. Thanks in advance for your help!
A jet moving at 500.0 km/h due east moves into a region where the wind is blowing at 120.0 km/h in a direction 30.0 degrees north of east. What is the new velocity and direction of the aircraft relative to the ground? Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
Cut a given sphere by a plane |
2007-03-14 |
 |
From Rory: Cut a given sphere by a plane so that the volumes of the two segments formed shall be in a given ratio.
Show that in modern notation, this leads to the cubic equation
m(r+x)^2(2r-x)=n(r-x)^2(2r+x)
where r is the radius of the sphere, x is the distance of the cutting plane from the centre of the sphere, and m/n < 1 is the given ratio.
Can you help me show the solution to this question. Thank you. Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
The distance from a point to a line in 3 space |
2006-10-29 |
 |
From Marie: find the distance from the point (1, -2, -3) to the line x = y = z-2 Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
Computing gravity |
2006-09-27 |
 |
From Patricia: What is the gravity of planet z in inch/hr squared if the weight of an element with mass of 45000 oz on planet z is 2N? Answered by Stephen La Rocque. |
 |
 |
 |
 |
 |
|
Plotting co-ordinates on a number plane |
2006-09-08 |
 |
From Victor: I need to plot co-ordinates (0,2), (2,-2), (-2,0), and (0,0) on a number or co-ordinates plane, I am not sure how to do this, and get lost after the first point, can you please help? Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
Flying with and against the wind |
2006-07-06 |
 |
From Tim: When a plane flies with the wind, it travels 800 miles in 4 hours. Against the wind it takes 5 hours to cover the same distance. Find the rate of the plane in still air and the rate of the wind. Answered by Stephen La Rocque. |
 |
 |
 |
 |
 |
|
A line parallel to a plane |
2006-03-28 |
 |
From Ryan:
I was wondering how I would prove the following theorem. I am completely lost at this point and all my other ideas have been extremely complicated and somewhat blurry.
"Through a point outside a given plane, there is at least one line parallel to the given plane."
Answered by Chris Fisher. |
 |
 |
 |
 |
 |
|
Find the ground speed and the planes true heading. |
2006-02-05 |
 |
From Jimmie: An aircraft going from city A to city B on a bearing of S69E (degrees) is traveling at a speed of 430 mph. The wind is blowing out of the north to south at a speed of 25 mph. Find the ground speed and the planes true heading. Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
How many passengers boarded the plane in Phoenix? |
2005-11-03 |
 |
From Vish: Passengers boarded a plane in Phoenix. In Dallas 1/2 of the passengers got off and 4/5 of the original number got on. In Memphis 3/4 of the passengers got off and twice the number of remaining passengers got on. In Chicago 2/3 of the passengers got off the plane leaving 39 passengers. How many passengers originally boarded the plane in Phoenix? Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
What is the radius of this planet |
2005-08-05 |
 |
From Kelly: Assuming that a North-South line has been established, you set up two camps that are 67 miles apart. You now set up poles at each camp perpendicular to the ground. On a certain day at "noon" the pole at the South camp casts no shadow, while at the North camp a shadow is cast. The shadow makes an angle of 89 degrees with the horizontal. What is the radius, diameter, and circumference of this planet? Answered by Chris Fisher. |
 |
 |
 |
 |
 |
|
An aircraft is flying directly from airport A to airport B |
2004-10-22 |
 |
From A student: In this question, i is a unit vector due east and j is a unit vector due north. An aircraft is flying directly from airport A to airport B, which is 2000 km from A. The velocity in still air of the aircraft is (150i+50j)km/h and the ground speed is (200i-30j)km/h. Calculate
(i) the time of flight, to the nearest min
(ii) the direction of the wind. Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
The intersection of planes |
2004-09-07 |
 |
From Joshua: I was wondering about the intersection of planes. Can planes intersect? Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
Two line segments and a plane |
2003-09-11 |
 |
From Laura: Do all figures made up of two segments lie in a plane? Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
Can 2 vertical planes intersect? |
2003-09-06 |
 |
From Erin: My question is can 2 vertical planes intersect? Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
A triangle in the complex plane |
2003-07-10 |
 |
From Scott: The vertices O and A of an EQUILATERAL triangle OAB in the complex plane are located at the origin and 3 + 3i. Find all possible values for the complex number representing the vertex B. Give the location of B in both polar and cartesian form (to 2.d.p) Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
Two trig problems |
2003-06-10 |
 |
From Bett:
I have this ongoing trouble with trig and solving triangles with laws of cosines and sines!! For example if it asks to solve triangle FGH, given angle G=102.7 , side f=14.2, and h=18.6. Now do I use law of cosines because I don't have the measure of an angle and length of the opposite side??I don't know where to go from here,I am totally confused!!! I also have a problem with this word problem I have been doing. It asks: An airplane flies 847.5 km at a bearing of 237.3 degrees. How far south and west fo its original position is it? Huh? Please help! Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
Two airplanes leave Dallas |
2003-02-06 |
 |
From A student: TWO AIRPLANES LEAVE DALLAS AT THE SAME TIME AND FLY IN OPPOSITE DIRECTIONS. ONE AIRPLANE TRAVELS 80 MILES PER HOUR FASTER THAN THE OTHER. AFTER THREE HOURS, THEY ARE 2940 MILES APART. WHAT IS THE RATE OF EACH AIRPLANE? Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
Two rate problems |
2002-09-30 |
 |
From Rebecca:
- There are two small holes in the bottom of a tub filled with water. If opened, one hole will empty the tub in three hours; the other will empty it in six hours. If both holes are opened at the same time, how long will it take to empty the tub?
- An airplane flies 400 miles per hour in calm air. It can cover 900 miles flying with the wind in the same time that it can cover 700 miles against the wind. What is the speed of the wind?
Answered by Penny Nom. |
 |
 |
 |
 |
 |
|
The radius of a planet |
2001-07-30 |
 |
From Jessica: A satellite is orbiting the earth at an altitude of 100 miles. If the angle of depression from the satellite to the horizon is 50 degrees, what is the radius (to the nearest mile) of the planet? Answered by Harley Weston. |
 |
 |
 |
 |
 |
|
How many planes contain a line and a point? |
2000-08-30 |
 |
From Harold: How many planes contain each line and point? Answered by Harley Weston. |
 |
 |
 |
 |
 |
|
Uniting algebra and geometry |
2000-04-16 |
 |
From Beth: Who is the mathmatician that united algebra and geometry??? Answered by Claude Tardif. |
 |
 |
 |
 |
 |
|
Parallel planes |
2000-01-10 |
 |
From Hugo Alvarez: When two parallel planes are cut by a third plane, the lines of the intersection are? Answered by Claude Tardif. |
 |
 |
 |
 |
 |
|
An airplane problem |
1999-03-08 |
 |
From B.M.R.: A plane left New York and headed East to its destination 3600 miles away across the Atlantic. On the way back its speed was boosted by a 50 mph tail wind and it arrived an hour early. What was its normal speed? Answered by Jack LeSage. |
 |
 |
 |
 |
 |
|
Intersection of Planes |
1998-12-03 |
 |
From Lindsay Fear: My name is Lindsay Fear. I am an OAC student (which is the Ontario equivalent to Grade 12 in most other states and provinces). I am in an Algebra and Geometry course and am currently studying a unit on equations of planes. Our teacher has given us this question that my friend and I have attempted several times, but we are still unable to solve it. My teacher has also suggested using the internet as a resource. The question is: Prove that a necessary condition that the three planes -x + ay + bz = 0 ax - y + cz = 0 bx + cy - z = 0 have a line in common is that a^2 + b^2 + c^2 + 2abc = 1 Answered by Walter Whiteley. |
 |
 |
 |
 |
 |
|
Intersection of planes |
1998-11-22 |
 |
From Dave Rasmussen: I am a teacher of secondary mathematics with a question about the uses of Three Dimensional Co-ordinate Geometry. I have been teaching my students to write equations of planes and lines, - to find the intersection of these and the distance between them. What I am having difficulty finding are good applications of these techniques to "real world" situations. Can anybody help me? Answered by Walter Whiteley and Harley Weston. |
 |
 |