Answer:
The answer is
<h2>2560 J</h2>
Explanation:
The kinetic energy of an object given it's mass and velocity can be found by using the formula
where
m is the mass
v is the velocity
From the question
m = 80 kg
v = 8 m/s
The kinetic energy is
We have the final answer as
<h3>2560 J</h3>
Hope this helps you
Answer:
A. Mass-extinction events are times in the Earth's history when few species evolve.
Explanation:
The extinction that occurred 65 million years ago wiped out some 50 percent of plants and animals. The event is so striking that it signals a major turning point in Earth's history, marking the end of the geologic period known as the Cretaceous and the beginning of the Tertiary period.
A wide range of animals and plants suddenly died out, from tiny marine organisms to large dinosaurs.
Species go extinct all the time. Scientists estimate that at least 99.9 percent of all species of plants and animals that ever lived are now extinct.
Answer:
D
Explanation:
A) is not correct, because the gravitation potential energy will depend on the height the block is located at. It will be calculated with the formula:
U=mgh.
If we take the ground as a zero height reference, then on point 2 the potential energy will be:
While on point 3, the potential energy will be greater.
B) is not the right answer because the kinetic energy will vary with the height the block is located at in the fact that the energy is conserved (this is if we don't take friction into account or air resistance) so in this case:
We already know the potential energy at point 2. We can calculate the kinetic energy at point 3 like this:
So the kinetic energy at point 2 is given by the equation:
so:
As you may see the kinetic energy at point 2 is greater than the kinetic energy at point 3.
C) Is not correct because according to the first law of thermodinamics, energy is not lost, only transformed. So, since we are not taking into account friction or any other kind of loss, then we can say that the amount of mechanical energy at point 1 is exactly the same as the mechanical energy at point 3.
D) Because of what we talked about on part C, this will be the true situation, because the mechanical energy of the block will be the same no matter theh point you measure it at.
a. A car driving in a straight line at 20 m/s.
Explanation:
An object is in a state of equilibrium when no force is acting upon it. There are two types of equilibrium; static equilibrium and dynamic equilibrium.
Static equilibrium is a state when a body is at rest.
Dynamic equilibrium is an equilibrium state when a body is moving at a constant velocity. (Rectilinear Motion).
A car moving in a straight line at 20 m/s has a constant velocity and hence no force is acting on it. So, it is in dynamic equilibrium.
A book sitting on a table without moving is not is dynamic equilibrium but in static equilibrium.
A boy jumping off a diving board in not in equilibrium as gravitational force is acting upon him and he has a changing velocity.
A motorcycle going in a circle at a constant speed has changing velocity because the direction of the motion is constantly changing hence it is not in the state of motion.
Keywords: velocity, force, equilibrium, static equilibrium, dynamic equilibrium
Learn more about dynamic equilibrium from brainly.com/question/12880727
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They have 6 faces
12 edges
8 edges
