Answer:
1.) h = 164.8 m
2.) U = 49.1 m/s
3.) t = 1.43 seconds
Explanation:
1.) A soccer ball is dropped from the top of a building. It takes 5.8 seconds to fall to the ground. The height of the building is...?
Since the soccer ball is dropped from the building, the initial velocity U will be equal to zero
Using second equation of motion
h = Ut + 1/2gt^2
Substitutes the time into the formula
h = 1/2 × 9.8 × 5.8^2
h = 164.8 m
2. The Falcon 9 launches to a height of 123 meters. What is its vertical initial velocity?
At maximum height final velocity = 0
Using the third law of motion
V^2 = U^2 - 2gH
0 = U^2 - 2 × 9.8 × 123
U^2 = 2410.8
U = 49.1 m/s
3. An apple falls from rest off a 10.m m tree. How long will it take before it hits the ground?
Since the apple fall from rest, the initial velocity U will be equal to zero
Using the second equation of motion,
h = Ut + 1/2gt^2
substitute all the parameters into the formula
10 = 1/2 × 9.8 × t^2
10 = 4.9t^2
t^2 = 10/4.9
t^2 = 2.04
t = 1.43 seconds
Let car A's starting position be the origin, so that its position at time <em>t</em> is
A: <em>x</em> = (40 m/s) <em>t</em>
and car B has position at time <em>t</em> of
B: <em>x</em> = 100 m - (60 m/s) <em>t</em>
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They meet when their positions are equal:
(40 m/s) <em>t</em> = 100 m - (60 m/s) <em>t</em>
(100 m/s) <em>t</em> = 100 m
<em>t</em> = (100 m) / (100 m/s) = 1 s
so the cars meet 1 second after they start moving.
They are 100 m apart when the difference in their positions is equal to 100 m:
(40 m/s) <em>t</em> - (100 m - (60 m/s) <em>t</em>) = 100 m
(subtract car B's position from car A's position because we take car A's direction to be positive)
(100 m/s) <em>t</em> = 200 m
<em>t</em> = (200 m) / (100 m/s) = 2 s
so the cars are 100 m apart after 2 seconds.
Assuming that the box is moving when it is being pulled, Work is done on the box.
So work is the Force times the distance
W=Fd
But what is work actually ? When something moves due to force over some change in distance, it have energy.
But where does this energy come from ? Does it magically appear ? The energy comes from the applied force onto the box.
So the energy have been transferred. And it’s like that throughout the universe
Now to save time, I’ll just tell you the answer: kinetic energy
:)
Answer:
Explanation:
Potential energy is the energy of a body due to is virtue of rest.
Potential energy is given as mgh
g is a constant and it is 9.81m/s²
And also the mass of the body is given as 1.3kg
Now the height of the body is
He took a book to a storey building of height 26m
He still holds the book 151 cm (1.51m) above the house.
The house is on an altitude of 1609m from the sea level.
Total Ug with out the sea level is
Ug=mgh
Ug=1.3 × 9.81 ×(26+1.51)
Ug=350.84J
Then, the potential energy due to the sea level is given as
Ug=mgh
Where g = 1/6371 m/s²
Therefore
Ug=mgh
Ug=1.3 × 1/6371 ×1609
Ug=0.328J
Total energy = 0.328+350.84
Ug=351.17J
Believe it or not white clouds can be both opaque and transparent depending on the volume and mass within that cloud. The heavier the cloud, the more opaque it'll seem, but the lighter the cloud is, it'll seem transparent-
