Question

The smoke from a gun barrel is seen 10s before the explosion is heard. If the speed of sound in air is $340m/s$. Calculate the distance of observer from the gun:
A) $3400m$
B) $2402m$
C) $62m$
D) $900m$

Answer 1

Speed is measured through how fast an object moves from one place to another. It is a scalar quantity. No movement in the object will lead to zero speed. There are two types of speed. Velocity is a vector quantity. Velocity means speed with direction. Agility means speed of action after the decision made by the particular person.

Formula used:
Formula for speed is, ${\text{Speed = }}\dfrac{{{\text{Distance}}}}{{{\text{Time}}}}$
This formula is also represented by symbols,
${\text{Speed}} = \Delta s/\Delta t$
Whereas, $\Delta$ means respective change
$\Delta s =$ change in speed
$\Delta t =$ change in time

Complete step by step solution:
It is given that,
The speed of sound in air $= 340m/s$
The smoke from a gun barrel is seen in $10s$, hence time is,
Time $= 10s$
By applying the formula,
${\text{Speed = }}\dfrac{{{\text{Distance}}}}{{{\text{Time}}}}$
But we have find the distance, so bringing the time to LHS side
${\text{Distance = Speed \times Time}}$
By putting the values speed and time in formula
Distance $= 340 \times 10m$
Distance $= 3400m$
$\therefore$ The distance of observer from the gun is $3400m$

Note:
Sound is a wave that travels through a medium like gas, liquid or water. Sound travels as a longitudinal wave in liquids and transverse waves in solids. The speed of sound travels depends on the medium which it travels. Sound speed is related to the speed of air. Usually light travels faster than the sound. Sound properties are pitch, loudness and tone. Distance is a scalar quantity.
Displacement $=$ final distance away from the point – initial distance. Meter [m] is the SI unit (International System of units) of distance and displacement.