Answer:
Explanation:
The equation fo potential energy is PE = mgh, where m is the mass of the ball, g is the pull of gravity (constant at 9.8), and h is the max height of the ball. What we do not have here is that height. We need to first solve for it using one-dimensional equations. What we have to know above all else, is that the final velocity of an object at its max height is always 0. That allows us to use the equation
where vf is the final velocity and v0 is the initial velocity. We will find out how long it takes for the object to reach that max height first and then use that time to find out what that max height is. Baby steps here...
0 = 21.5 + (-9.8)t and
-21.5 = -9.8t so
t = 2.19 seconds (Keep in mind that if I used the rules correctly for sig fig's, the answer you SHOULD get is not one shown, so I had to adjust the sig fig's and break the rules. But you know what they say about rules...)
Now we will use that time to find out the max height of the object in the equation
Δx =
and filling in:
Δx =
which simplifies down a bit to
Δx = 47.1 - 23.5 so
Δx = 23.6 meters.
Now we can plug that in to the PE equation to find the PE of the object:
PE = (.19)(9.8)(23.6) so
PE = 43.9 J
The problem is basically asking us to find a way to find the sound intensity I, in terms dependent on the sound level and the reference intensity
.For this purpose we can start from the unit used in the scale logarithmic decibel, that is

Where
I = Acoustic intensity on the linear scale
Hearing threshold
Using the logarithmic properties of the exponents the above expression can be described as:

that is the expression or technique to find the intensity of sound.
Answer:
15.64 KN
Explanation:
mass of the elevator cab with a single occupant= 2300 kg
acceleration relative to the cab
= 6.80 m/s^2
acceleration of the coin relative to the cab in the opposite direction of motion of cab so we can consider it as a= -6.80 m/s^2
The acceleration of elevator cab relative to the ground 
now we can say that

=-6.80+ a_{eg}= -9.8
[tex]a_{eg}=-9.8+6.80=-3.8
The forces that act on elevator cab are tension and gravitational, applying newtons second law
T- mg= ma_{eg}
Then the tension in the cable is
T= 2300(-3.8)+2300×9.8= 15640 N= 15.64 KN
therefore tension in the string will be 15.64 KN
The final velocity is 3.47 m/s east
Explanation:
We can solve this problem by using the law of conservation of momentum. In fact, the total momentum of the two players before and after the collision must be conserved:
where:
is the mass of the first player
is the initial velocity of the first player (we take east as positive direction)
is the mass of the second player
is the initial velocity of the second player
is their final combined velocity after the collision
Re-arranging the equation and substituting the values, we find:
So, their velocity afterwards is 3.47 m/s east.
Learn more about momentum:
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Answer:
The magnitude of gravitational force between two masses is
.
Explanation:
Given that,
Mass of first lead ball, 
Mass of the other lead ball, 
The center of a large ball is separated by 0.057 m from the center of a small ball, r = 0.057 m
We need to find the magnitude of the gravitational force between the masses. It is given by the formula of the gravitational force. It is given by :

So, the magnitude of gravitational force between two masses is
. Hence, this is the required solution.