Calculating Resultant Velocity with Vector Diagrams

In summary, the resultant velocity of a horizontal and a vertical velocity can be calculated using the parallelogram rule, where the vectors are added and the pythagorean theorem and trigonometric functions are used to find the magnitude and angle of the resultant velocity. In the case where the velocities are at right angles, the parallelogram rule simplifies to a rectangle, making the calculations easier.
  • #1
Gogsey
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Is the result of a horizontal velocity and a vertical velocity caluculated by a vertor diagram whereby the resultant velocity is at 45 degrees from the horizontal?

If not, is is something to do with angles, please explain!
 
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  • #2
Nope,45° will be opnly in the particular case in which the velocities will be equal in modulus...

Apply the "paralelogramme rule"...Add the vectors and use the pythagorean theorem and the (circular) trigonometrical functions...

Daniel.
 
  • #3
Ok, thanks for the reply, but this doesn't help me to much.

The veloicties are directly along the vertical and horizontal axis.

Why is the paralleogram rule needed?
I get why you use pythogorean theorem(i think), and do you use the trig functions to calculate the eultant velocties angle from the vertical plane?

So you use pythagorean theorem to find the magnitude of the resultant velocity.

vertical V squared + horizontal V squared = resultant V squared

And the angle form the vertical is calculated by using the tan rule of opp over adj.(The values of the opp and adj being the horizontal and vertical velocities).
 
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  • #4
Exactly right.

You're still using the parallelogram rule. It's just in this case, with the vectors being at right angles to each other, you happen to have a special case where your parellelogram happens to be a rectangle (this is the easiest case of the parellogram rule).
 
  • #5
I see what you mean now. Since the velocities are both on the horizontal and vertical planes, and drawing in the other lines would give you the parallelogram, or in this case, a rectangle.
 

FAQ: Calculating Resultant Velocity with Vector Diagrams

1. How do you calculate resultant velocity with vector diagrams?

To calculate resultant velocity with vector diagrams, you first need to draw a scale diagram of the vectors representing the different velocities. Then, you can use the Pythagorean theorem to find the magnitude of the resultant velocity and trigonometric functions to determine its direction.

2. What is the Pythagorean theorem and how does it apply to calculating resultant velocity?

The Pythagorean theorem states that in a right triangle, the square of the length of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the other two sides. In the context of calculating resultant velocity, this theorem is used to find the magnitude of the resultant velocity by adding the squares of the individual velocities and taking the square root of the sum.

3. How do you determine the direction of the resultant velocity using trigonometric functions?

To determine the direction of the resultant velocity, you can use trigonometric functions such as sine, cosine, and tangent. These functions relate the lengths of the sides of a right triangle to its angles. By finding the appropriate angle and using the inverse of the trigonometric function, you can determine the direction of the resultant velocity.

4. Can you explain the difference between speed and velocity?

Speed is a scalar quantity that refers to how fast an object is moving, regardless of its direction. Velocity is a vector quantity that refers to the speed and direction of an object. This means that two objects can have the same speed but different velocities if they are moving in different directions.

5. Is it necessary to use vector diagrams to calculate resultant velocity?

No, it is not always necessary to use vector diagrams to calculate resultant velocity. If the velocities are along the same line, you can simply add or subtract them to find the resultant velocity. However, if the velocities are not collinear, vector diagrams are a helpful tool to visualize and accurately calculate the resultant velocity.

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