In component form, the displacement vectors become
• 350 m [S] ==> (0, -350) m
• 400 m [E 20° N] ==> (400 cos(20°), 400 sin(20°)) m
(which I interpret to mean 20° north of east]
• 550 m [N 10° W] ==> (550 cos(100°), 550 sin(100°)) m
Then the student's total displacement is the sum of these:
(0 + 400 cos(20°) + 550 cos(100°), -350 + 400 sin(20°) + 550 sin(100°)) m
≈ (280.371, 328.452) m
which leaves the student a distance of about 431.8 m from their starting point in a direction of around arctan(328.452/280.371) ≈ 50° from the horizontal, i.e. approximately 431.8 m [E 50° N].
Answer:
Explanation:
For sound level in decibel scale the relation is
dB = 10 log I / I₀ where I₀ = 10⁻¹² and I is intensity of sound whose decibel scale is to be calculated .
Putting the given values
61 = 10 log I / 10⁻¹²
log I / 10⁻¹² = 6.1
I = 10⁻¹² x 10⁶°¹

intensity of sound of 5 persons


= 10log 5 x 10⁶°¹
= 10( 6.1 + log 5 )
= 67.98
sound level will be 67.98 dB .
The answer to the question