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olganol [36]
3 years ago
12

A 0.15-kg ball is thrown into the air and rises to a height of 20.0 m. How much kinetic energy did the ball initially have?

Physics
2 answers:
zzz [600]3 years ago
7 0
IF the toss was straight upward, then the kinetic energy it got
from the toss is the gravitational potential energy it has at the top,
where it stops rising and starts falling.

Potential energy =  (mass)  x   (gravity) x (height)

                           = (0.15 kg) x (9.8 m/s²) x (20 m)

                           =      29.4 kg-m²/s²  =  29.4 joules .
mel-nik [20]3 years ago
3 0
The conservation of energy says that energy in an isolated system remains constant, that it is not created nor destroyed but transforms from one form of energy to another. 
So when the ball is thrown into the air, it has kinetic energy (KE). As it goes into the air, that kinetic energy transforms into gravitational potential energy (GPE). The higher it gets, the more GPE it has and therefore the less KE it has. 
At the top, all of it is transformed into GPE and there is no KE.
But total energy at any point after the ball is thrown until it lands it has the same energy throughout. 

Knowing this, you can set the beginning KE equal to the final GPE. 
KE = GPE

Insert formula for GPE.

KE = mgh
KE = 0.15kg*9.8m/s^2*20.0m
KE = 29 J

The ball initially had 29 J of kinetic energy
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Alex Ar [27]

Answer:

750 J

Explanation:

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3 0
3 years ago
A speaker emits sound waves in all directions, and at a distance of 28 m from it the intensity level is 73 db. What is the total
Oduvanchick [21]

Answer:

P=0.197 Watt

Explanation:

Given That

B=73dB

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6 0
3 years ago
A wire, 1.0 m long, with a mass of 90 g, is under tension. A transverse wave is propagated on the wire, for which the frequency
Mice21 [21]

Answer:

T = 712.9 N

Explanation:

First, we will find the speed of the wave:

v = fλ

where,

v = speed of the wave = ?

f = frequency = 890 Hz

λ = wavelength = 0.1 m

Therefore,

v = (890 Hz)(0.1 m)

v = 89 m/s

Now, we will find the linear mass density of the wire:

\mu = \frac{m}{L}

where,

μ = linear mass density of wie = ?

m = mass of wire = 90 g = 0.09 kg

L = length of wire = 1 m

Therefore,

\mu = \frac{0.09\ kg}{1\ m}

μ = 0.09 kg/m

Now, the tension in wire (T) will be:

T = μv² = (0.09 kg/m)(89 m/s)²

<u>T = 712.9 N</u>

7 0
3 years ago
What is energy?
mestny [16]

Answer:

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6 0
3 years ago
Which formula represents final velocity of an object with average acceleration?
zheka24 [161]

Answer:

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Explanation:

hope this is it

5 0
2 years ago
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