Answer:
b. varies inversely with the square of the distance from the center of Earth.
Explanation:
Comparing the Newton's law of universal gravitation and second law of motion;
from Newton's second law of motion,
F = ma ............. 1
from New ton's law of universal gravitation,
F = 
........... 2
Equating 1 and 2, we have;
mg =
g = 
Therefore, the acceleration due to gravity near Earth, g, is inversely proportional to the square of the distance from the center of Earth.
Answer:
Acceleration is the change in velocity, not the velocity itself; therefore, an object can have zero velocity but not zero acceleration because the velocity will be changing.
This year is 60 years since I learned this stuff, and one of the things I always remembered is the formula for the distance a dropped object falls:
D = 1/2 A T²
Distance = (1/2) (acceleration) (time²)
The reason I never forgot it is because it's SO useful SO often. You really should memorize it. And don't bury it too deep in your toolbox ... you'll be needing it again very soon. (In fact, if you had learned it the first time you saw it, you could have solved this problem on your own today.)
The problem doesn't tell us what planet this is happening on, so let's make it easy and just assume it's on Earth. Then the 'acceleration' is Earth gravity, and that's 9.8 m/s² .
In 5 seconds:
D = 1/2 A T²
D = (1/2) (9.8 m/s²) (5 sec)²
D = (4.9 m/s²) (25 sec²)
D = 122.5 meters
In 6 seconds:
D = 1/2 A T²
D = (1/2) (9.8 m/s²) (6 sec)²
D = (4.9 m/s²) (36 sec²)
D = 176 meters
Answer:
f>1000Hz and wavelength=0.343 m
Explanation:
We are given that
Frequency of stationary siren,f=1000 Hz
Wavelength of stationary sound,
When a observer is moving towards the siren then the frequency increases.
Therefore,an observer who is moving towards the siren measure a frequency >1000 Hz.
The wavelength depends upon the speed of source.
But we are given that siren is stationary.
Therefore, source is not moving and then the wavelength remains same.
f>1000Hz and wavelength=0.343 m
