Determing speed using time?

Question

i was wondering what kind of math is involved in determining the speed/velocity of an object crossing a certain area in a specific amount of time. Like if I had a 12 inch square box drawn on a floor, if an object crossed that whole box in X seconds, how would you figure out the speed of said object?

Answer 1

Speed = distance/time

Answer 2

physics and 2d Kinematic equations

Answer 3

It really isn't any harder than speed = distance/time

The trick is figuring the distance.  If you cross the box in a straight

line from one side to another the distance is 12. If cross from one

corner to the other the distance is sqrt(2)*12.

If you cross into the square and stagger around randomly for a while

until leaving it, you'd have to figure out a way to measure the length

of the path. That's the real problem.

Answer 4

Velocity = v

Distance = d

Time = t

v = d/t

NOTE: This equation is not for acceleration of an object. The equation only works if the object in question has a CONSTANT (non-changing) velocity.

Answer 5

Speed = Distance / Time

You have an additional problem here.

Find the distance traveled by an object that crosses a 12 inch square.

The object travels across the square covering 12 inches with some width.

The width is necessary for finding out the total distance.

If the object has a width of 1 inch, then it takes 12 trips to cover the entire square, plus 11 moves of one inch to get from one "stripe" to the next.  Total distance = 12*12 + 11*1 = 144 + 11 = 155.

If the object has a width of 2 inches, it takes 6 trips to cover the square plus 5 moves of 2 inches.

You could write a general equation for width "w inches" if necessary.

The math involved:

arithmetic and geometry

some algebra for a general solution.

Answer 6

Speed is a rate of travel. An object travelling 35 feet in one second is moving 35 feet/second.

If your object crosses the box perpendicular to its edges, you can know that it travels 12 inches pretty easily. The time it takes gives away the rate: 12 inches per X seconds. Since 12 inches is one foot, you also know your object is travelling 1 foot per X seconds.

This rate is the inverse of what we normally see, though. Say your timing finds it takes 3.5 seconds to travel one foot. "1 foot per 3.5 seconds" is the reciprocal of the rate we normally see. To find a better representation, simply take the reciprocal of the time: 1/x.  1/3.5 is 0.286, so you end up with 0.286 feet per second.

You can do similar math to find th rate in a more convenient measure. For example, since one foot is 12 inches, you can divide 12 by 3.5, giving 3.429 inches per second.