Vectors/Trigonometry Notation Problem

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In summary, a vector is a mathematical object with both magnitude and direction, commonly represented by an arrow. In trigonometry, vectors are represented by their magnitude and direction in terms of angles. The difference between a scalar and a vector is that a scalar only has magnitude, while a vector has both magnitude and direction. Vectors can be added or subtracted using the head-to-tail or parallelogram method. The Pythagorean theorem, which states that the square of the hypotenuse is equal to the sum of the squares of the other two sides, is related to vectors as it can be used to find the magnitude of a resultant vector.
  • #1
lando45
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Hey,

I have been set this question:

The instantaneous acceleration of a runner as she rounds the curve on a track is <-1.5 , 0.5> m/s2.What is the magnitude of the acceleration of the runner and what angle does this vector make with respect to the +x axis?

But I don't really understand what the question is asking for, and what the <-1.5 , 0.5> means...any help?

Thanks a lot
 
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  • #2
I imagine that <-1.5 , 0.5> are the components of her acceleration. i.e. her accln in the x-direction is -1.5 m/s² and in the y-direction, it's 0.5 m/s²


Does that help ?
 
  • #3
for reaching out for clarification on this question. It seems like you are struggling with the notation used in this problem. Let's break it down step by step.

First, the notation used in this problem is called vector notation. It is used to represent both the magnitude and direction of a physical quantity, in this case, acceleration. The notation is written as <x, y>, where x represents the magnitude of acceleration in the x-direction and y represents the magnitude of acceleration in the y-direction.

In this problem, the notation is < -1.5, 0.5 > m/s2. This means that the acceleration of the runner in the x-direction is -1.5 m/s2 and in the y-direction is 0.5 m/s2. The negative sign indicates that the acceleration is in the opposite direction of the positive x-axis.

Now, to answer the question, we need to find the magnitude of the acceleration and the angle it makes with respect to the +x axis. To find the magnitude, we can use the Pythagorean theorem, which states that the magnitude of a vector <x, y> is equal to the square root of x^2 + y^2. In this case, the magnitude of acceleration is √((-1.5)^2 + (0.5)^2) = √(2.25 + 0.25) = √2.5 m/s2.

To find the angle, we can use trigonometry. The angle with respect to the +x axis is given by the inverse tangent of y/x. In this case, the angle is tan^-1(0.5/-1.5) = -18.43 degrees. Note that the negative sign indicates that the angle is in the opposite direction of the positive x-axis.

I hope this helps to clarify the notation and how to solve this problem. If you have any further questions, please don't hesitate to ask. Good luck!
 

1. What is a vector?

A vector is a mathematical object that has both magnitude (size) and direction. It is commonly represented by an arrow in a specific direction and can be used to describe physical quantities such as velocity, force, and displacement.

2. How is a vector represented in trigonometry?

In trigonometry, a vector is typically represented by its magnitude and direction in terms of angles. This is often done using the notation (r, θ), where r is the length of the vector and θ is the angle it makes with the positive x-axis.

3. What is the difference between a scalar and a vector?

A scalar is a quantity that has only magnitude, while a vector has both magnitude and direction. Examples of scalars include temperature, mass, and time, while examples of vectors include displacement, velocity, and force.

4. How do you add or subtract vectors?

To add or subtract vectors, you can use the head-to-tail method or the parallelogram method. In the head-to-tail method, you place the tail of one vector at the head of the other and draw a vector from the tail of the first vector to the head of the second vector. In the parallelogram method, you draw the two vectors from the same point and create a parallelogram. The resulting diagonal of the parallelogram is the sum or difference of the two vectors.

5. What is the Pythagorean theorem and how is it related to vectors?

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 lengths of the other two sides. In the context of vectors, this theorem can be used to find the magnitude of a resultant vector when two vectors are added using the head-to-tail method.

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