Answer:
Ff = u M g frictional force where u = .62
1/2 M v^2 kinetic energy of water bottle at release
Ff * d = 1/2 M v^2 = u M g d work to stop equals initial kinetic energy
v^2 = 2 u g d = 2 * .62 * 9.8 * 12 = 146 m^2 / s^2
v = 12.1 m/s
Answer:
far from the speaker the intensity drops to 85 dB.
Explanation:
In the equation for the Decibel scale

The ratio of the intensities can be written as


And since

and
,

meaning

Putting this into equation (1), we get:

Now, if the intensity is 100 dB when the distance is 5 meters, we have:


by taking both sides to the exponent:


Now equation (2) becomes

when the intensity level is 85 dB we have


take both sides to exponents and we get:




Thus,
far from the speaker the intensity drops to 85 dB.
Answer:
An elastic collision is a collision in which there is no net loss in kinetic energy in the system as a result of the collision. Both momentum and kinetic energy are conserved quantities inelastic collisions.
Explanation:
Suppose two similar trolleys are traveling toward each other with equal speed. They collide, bouncing off each other with no loss in speed. This collision is perfectly elastic because no energy has been lost. In reality, examples of perfectly elastic collisions are not part of our everyday experience. Some collisions between atoms in gases are examples of perfectly elastic collisions. However, there are some examples of collisions in mechanics where the energy lost can be negligible. These collisions can be considered elastic, even though they are not perfectly elastic. Collisions of rigid billiard balls or the balls in Newton's cradle are two such examples.