A famous celebrity has an extreme security system for their estate. The security system includes sensors in the ground as well as on the sides of the buildings. A loud truck drives down the road entering the estate. There is a sensor in the ground and another on the side of the security guard’s shed. If both sensors are 100m from the truck, which sensor will pick up the noise of the truck first and why?

A.
Guard Shed - The sensor on the security guard’s shed will detect the sound first because the sound is traveling through the air and sound will travel fastest through a gas.

B.
Ground - The sensor in the ground will detect the sound first because the sound is traveling through the dirt and sound will travel fastest through a solid.

C.
Same time - Because the sound is traveling through both the ground and the air at the same time, it will reach both the shed and the ground sensor at the same time.

D.
Neither sensor - 100m is too far for the sound to travel. Neither sensor will pick up the sound of the truck until it is closer to them.

B. Ground - The sensor in the ground will detect the sound first because the sound is traveling through the dirt and sound will travel fastest through a solid.

Explanation:

Sound wave is an example of mechanical wave, which means sound waves require a medium to travel through. However, how fast a sound travels is dependent on the kind of medium it travels through. Sound travels fastest via a SOLID medium, then liquid and slowest through gases.

According to this question, sensor in the ground and side of the security guard’s shed were placed in an estate owned by a famous celebrity. A loud truck, then, drives down the road entering the estate.

Based on the principles of sound eaves movement, the sound from the truck will be picked by the sensors in the GROUND first because the sound is traveling through the dirt and sound will travel fastest through a solid.