When an item is raised, the work is done in opposition to gravity. When an item is worked on, energy is transmitted to it, and it develops gravitational potential energy. If the same thing falls from that height, gravity must do the same amount of effort to bring it back to the Earth's surface.
By Newton's second law,
<em>n</em> + (-<em>w</em>) = 0
<em>p</em> + (-<em>f</em> ) = (20 kg) (2 m/s²)
where <em>n</em> is the magnitude of the normal force, <em>w</em> is the weight of the box, <em>p</em> is the magnitude of the applied force (<em>p</em> for <u>p</u>ush or <u>p</u>ull), and <em>f</em> is the magnitude of the friction force.
Calculate the weight of the box:
<em>w</em> = (20 kg) (9.80 m/s²) = 196 N
Then
<em>n</em> = <em>w</em> = 196 N
and
<em>f</em> = <em>µ</em> <em>n</em> = 0.5 (196 N) = 98 N
Now solve for <em>p</em> :
<em>p</em> - 98 N = 40 N
<em>p</em> = 138 N
The height above the ground from where the skier start is 11.5 m.
<h3>
Conservation of energy</h3>
The height above the ground from where the skier start is determined by applying the principle of conservation of energy as shown below;
P.E = K.E
mgh = ¹/₂mv²
gh = ¹/₂v²
Thus, the height above the ground from where the skier start is 11.5 m.
Learn more about conservation of energy here: brainly.com/question/166559
Answer:
6.78571 m/s
55.13387 Joules
Explanation:
= Velocity of squid = 2.5 m/s
= Velocity of water
= Mass of water = 1.75 kg
Mass of squid
Momentum of squid
As the momentum of the system is conserved
The speed of the water is 6.78571 m/s
Kinetic energy the squid creates is given by
Kinetic energy of the squid + Kinetic energy of water
Kinetic energy the squid creates by this maneuver is 55.13387 Joules
Answer : Option D) A dropped wallet is kicked around the floor of a busy train station.
Explanation : The description that best suits the model for the energy transfer that occurs in the radiative zone is -
<h3>A dropped wallet is kicked around the floor of a busy train station.</h3>
As in the radiation zone, which is also called as radiative zone or radiative region in the layer of a star's interior where energy is primarily transported toward the exterior by means of radiative diffusion and thermal conduction. This can be correlated with the example of a dropped wallet in a busy train station as the wallet would be kicked by many people who are in a hurry to travel, this represents the radiative diffusion. So, every time the wallet is being kicked by someone the energy is getting transformed.
