Answer:
r₂ = 0.2 m
Explanation:
given,
distance = 20 m
sound of average whisper = 30 dB
distance moved closer = ?
new frequency = 80 dB
using formula

I₀ = 10⁻¹² W/m²
now,



to hear the whisper sound = 80 dB



we know intensity of sound is inversely proportional to square of distances



r₂ = 0.2 m
First, let's put 22 km/h in m/s:

Now the radial force required to keep an object of mass m, moving in circular motion around a radius R, is given by

The force of friction is given by the normal force (here, just the weight, mg) times the static coefficient of friction:

Notice we don't use the kinetic coefficient even though the bike is moving. This is because when the tires meet the road they are momentarily stationary with the road surface. Otherwise the bike is skidding.
Now set these equal, since friction is the only thing providing the ability to accelerate (turn) without skidding off the road in a line tangent to the curve:
Answer:
Machine - A device consisting of fixed and moving parts that modifies mechanical energy and transmits it in a more useful form.
Mechanical advantage - Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system.
Inclined Plane - A plane set at an angle to the horizontal, especially a simple machine used to raise or lower a load by rolling or sliding.
Wedge - A piece of material, such as metal or wood, thick at one edge and tapered to a thin edge at the other for insertion in a narrow crevice, used for splitting, tightening, securing, or levering.
Screw - A cylindrical rod incised with one or more helical or advancing spiral threads, as a lead screw or worm screw.
Lever - A simple machine consisting of a rigid bar pivoted on a fixed point and used to transmit force, as in raising or moving a weight at one end by pushing down on the other.
Nosebleeds can be caused by being up in a very high altitude. As you climb higher, the amount of oxygen in the air decreases. This makes the air thinner and dryer, which can in turn cause the inside of your nose to crack and bleed.F
The answer to this question is Helium