Question

Two forces of magnitudes 3 units and 5 units act at 600 with each other.
What is the magnitude of their resultant?

Answer 1

Use the formula.... under root 3²+5²+2×15cos60

You'll get the answer

Answer 2

Correct Question :

Two forces of magnitudes 3 units and 5 units act at 60° with each other. What is the magnitude of their resultant?

Solution :

■ By parallelogram law of vector addition, the magnitude of resultant vector R of two vectors x and y inclined to each other at angle α is given by

• R² = x² + y² + 2(x)(y) cosα

By substituting the given values,

• x = 3 units
• y = 5 units
• α = 60°

➠ R² = 3² + 5² + 2(3)(5) cos60°

➠ R² = 9 + 25 + 30 (1/2)

➠ R² = 34 + 15

➠ R² = 49

➠ R = √49

➠ R = 7 units

$\star$ Additional Information :

• The latin word vector means carrier.
• The physical quantities which have no specified direction and ha e different values in different directions are called tensors. For example, moment of inertia
• A vector whose initial point is fixed is called localised vector and whose initial point is not fixed is called non-localised vector$.$