The acceleration of gravity is inversely proportional to
the square of the distance from Earth's center.
The acceleration of gravity is 9.8 m/s² on the Earth's surface ...
6380 km from the center.
If the acceleration of gravity at 'h' is 4.9 m/s² ... 1/2 of what it is
on the surface, then the distance from the center is
(6380 x √2) = 9,023 km (rounded) ,
and 'h' is the distance above the surface
= (9,023 - 6,380) = 2,643 km (rounded) .
Answer:
20.2
Explanation: Divide 726/34 and you get 20.16 round it and you get 20.2
Answer:
option (D) is correct.
Explanation:
According to the work energy theorem, the work done by all forces is equal to the change in kinetic energy of the body.
the kinetic energy of a body is directly proportional to the square of the speed of the body.
As the kinetic energy change, the speed of the body also change.
Option (D) is correct.
Answer:
The frequencies are 
Explanation:
From the question we are told that
The length of the ear canal is 
The speed of sound is assumed to be 
Now taking look at a typical ear canal we see that we assume it is a closed pipe
Now the fundamental harmonics for the pipe(ear canal) is mathematically represented as

substituting values


Also the the second harmonic for the pipe (ear canal) is mathematically represented as
substituting values
Given that sound would be loudest in the pipe at the frequency, it implies that the child will have an increased audible sensitivity at this frequencies