Vectors - Problems - Cosine of angle between vectors

  • Introduction to cosine of angle between vectors
  • The cosine of the angle between two vectors is a useful concept in vector algebra
  • It helps us determine the angle between two vectors in a geometric manner Examples:
  • Let A = 2i + j and B = i - 3j. Find the angle between A and B.
  • Given vectors C = -4i + j and D = 3i + 5j. Calculate the angle between C and D. Equation:
  • The equation to calculate the cosine of the angle between two vectors is given by:
    • cosθ = (A · B) / (|A| |B|) Note:
  • It is important to remember that the result of the cosine of the angle between two vectors lies between -1 and 1, inclusive.

Slide 21:

Title: Vectors - Problems - Scalar triple product

  • Introduction to scalar triple product
  • The scalar triple product is a scalar quantity resulting from the multiplication of three vectors
  • It helps us determine the volume of a parallelepiped formed by three vectors Examples:
  • Find the scalar triple product of vectors A = 2i + j - 3k, B = i - 3j + 2k, and C = 3i + 2j - k.
  • Calculate the scalar triple product of vectors D = -4i + j + 2k, E = 2i - 5j + 6k, and F = 3i + 5j + 7k. Equation:
  • The equation to calculate the scalar triple product of three vectors A = (a1, a2, a3), B = (b1, b2, b3), and C = (c1, c2, c3) is given by:
    • (A × B) · C = A · (B × C) Note:
  • The scalar triple product allows us to analyze the volume of a parallelepiped formed by three vectors.

Slide 22:

Title: Vectors - Problems - Vector triple product

  • Introduction to vector triple product
  • The vector triple product is a vector quantity resulting from the multiplication of three vectors
  • It helps us determine the direction of a vector perpendicular to two other vectors Examples:
  • Find the vector triple product of vectors A = 2i + j - 3k, B = i - 3j + 2k, and C = 3i + 2j - k.
  • Calculate the vector triple product of vectors D = -4i + j + 2k, E = 2i - 5j + 6k, and F = 3i + 5j + 7k. Equation:
  • The equation to calculate the vector triple product of three vectors A = (a1, a2, a3), B = (b1, b2, b3), and C = (c1, c2, c3) is given by:
    • (A × B) × C = B(A · C) - C(A · B) Note:
  • The vector triple product allows us to determine a vector that is perpendicular to two other vectors.

Slide 23:

Title: Vectors - Problems - Collinear and Coplanar Vectors

  • Introduction to collinear vectors
  • Collinear vectors are vectors that lie on the same line or are parallel to each other
  • They have the same or opposite direction but different magnitudes Examples:
  • Determine if the vectors A = 2i + j - 3k and B = 4i + 2j - 6k are collinear.
  • Check if the vectors C = -4i + j + 2k and D = -8i + 2j + 4k are collinear. Equation:
  • The equation to check if two vectors A and B are collinear is:
    • A = kB or A = -kB, where k is a scalar value Note:
  • Collinear vectors have the property that one vector is a scalar multiple of the other.

Slide 24:

Title: Vectors - Problems - Collinear and Coplanar Vectors (Contd.)

  • Introduction to coplanar vectors
  • Coplanar vectors are vectors that lie in the same plane
  • They can be added or subtracted to give a resultant vector lying in the same plane Examples:
  • Verify if the vectors A = 2i + j - 3k, B = 4i + 2j - 6k, and C = -2i - j + 3k are coplanar.
  • Check if the vectors D = -4i + j + 2k, E = -8i + 2j + 4k, and F = -2i - j - 2k are coplanar. Equation:
  • The equation to check if three vectors A, B, and C are coplanar is:
    • (A × B) · C = 0 or (B × C) · A = 0 Note:
  • Coplanar vectors lie in the same plane and can be represented by a two-dimensional coordinate system.

Slide 25:

Title: Vectors - Problems - Motion in a plane

  • Introduction to motion in a plane
  • Motion in a plane involves the movement of an object along two perpendicular directions
  • It is commonly represented using vectors and involves concepts like displacement and velocity Examples:
  • A car moves 5 km north and then 3 km east. Find the total displacement of the car.
  • An airplane travels 1000 km at an angle of 30 degrees northeast. Determine its eastward and northward components of displacement. Equation:
  • The equation to calculate the displacement in a plane is given by:
    • Displacement = √(dx^2 + dy^2) Note:
  • In motion in a plane, vectors are used to represent both direction and magnitude of displacement.

Slide 26:

Title: Vectors - Problems - Motion in a plane (Contd.)

  • Introduction to velocity in a plane
  • Velocity in a plane represents the rate of change of displacement with respect to time
  • It is a vector quantity and involves both magnitude and direction Examples:
  • A ball moves 10 m south in 2 seconds and then 5 m east in 1 second. Calculate the average velocity of the ball.
  • A cyclist travels 20 km/hr at an angle of 45 degrees north of east. Determine the northward and eastward components of velocity. Equation:
  • The equation to calculate the average velocity in a plane is given by:
    • Average Velocity = Displacement / Time Note:
  • Velocity in a plane is measured in units of distance per unit time and includes both magnitude and direction.

Slide 27:

Title: Vectors - Problems - Motion in a plane (Contd.)

  • Introduction to relative velocity in a plane
  • Relative velocity in a plane represents the velocity of one object with respect to another object
  • It is a vector quantity and involves both magnitude and direction Examples:
  • Two cars are moving in the same direction. Car A moves at 60 km/hr, and car B moves at 40 km/hr. Calculate the relative velocity of car B with respect to car A.
  • Two airplanes are flying towards each other. Airplane A has a velocity of 500 km/hr, while airplane B has a velocity of 400 km/hr. Determine the relative velocity of airplane A with respect to airplane B. Equation:
  • The equation to calculate the relative velocity in a plane is given by:
    • Relative Velocity = Velocity of Object A - Velocity of Object B Note:
  • Relative velocity in a plane helps us understand the motion of one object with respect to another object.

Slide 28:

Title: Vectors - Problems - Motion in a plane (Contd.)

  • Introduction to projectile motion
  • Projectile motion involves the motion of an object under the influence of gravity
  • The object follows a curved path and can be analyzed using both horizontal and vertical components Examples:
  • A ball is thrown horizontally with a velocity of 20 m/s. Calculate the horizontal and vertical components of its initial velocity.
  • A rocket is launched at an angle of 60 degrees above the horizontal with a velocity of 100 m/s. Determine the horizontal and vertical components of its initial velocity. Equation:
  • The equations to calculate the horizontal and vertical components of velocity in projectile motion are given by:
    • Horizontal Component: Vx = V * cosθ
    • Vertical Component: Vy = V * sinθ Note:
  • Projectile motion involves the motion of an object in a curved path under the influence of gravity.

Slide 29:

Title: Vectors - Problems - Motion in a plane (Contd.)

  • Introduction to circular motion
  • Circular motion involves the motion of an object in a circular path around a central point
  • It can be analyzed using both linear and angular velocities Examples:
  • A car is moving around a circular track with a radius of 100 m at a speed of 10 m/s. Calculate the linear velocity and angular velocity of the car.
  • A ferris wheel has a radius of 20 m and completes one revolution in 2 minutes. Determine the linear velocity and angular velocity of a passenger on the ferris wheel. Equation:
  • The equations to calculate the linear and angular velocities in circular motion are given by:
    • Linear Velocity: V = ω * r
    • Angular Velocity: ω = Δθ / Δt Note:
  • Circular motion involves the motion of an object in a circular path, and the velocity can be analyzed using linear and angular components.

Slide 30:

Title: Vectors - Problems - Motion in