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2 years ago

15

Lucifer is sitting in a tree that is 15 m above the ground. She jumps straight off the tree in the horizontal direction and land

s 7 m away from the base of the tree. How fast did she jump off the tree?

1 answer:

-BARSIC- [3]2 years ago

4 0

Answer:

huppp huppp huppp huppp huppp huppp

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A rotating paddle wheel is inserted in a closed pot of water. The stirring action of the paddle wheel heats the water. During th

fgiga [73]

Answer:

the final energy of the system is 35.5 kJ.

Explanation:

Given;

initial energy of the system, E₁ = 10 kJ

heat transferred to the system, q₁ 30 kJ

Heat lost to the surrounding, q₂ = 5kJ

heat gained by the system, Q = q₁ - q₂ = 30 kJ - 5kJ = 25 kJ

work done on the system, W = 500 J = 0.5 kJ

Apply first law of thermodynamic,

ΔU = Q + W

where;

ΔU is change in internal energy

Q is the heat gained by the system

W is work done on the system

ΔU = 25kJ + 0.5 kJ

ΔU = 25.5 kJ

The final energy of the system is calculated as;

E₂ = E₁ + ΔU

E₂ = 10 kJ + 25.5 kJ

E₂ = 35.5 kJ.

Therefore, the final energy of the system is 35.5 kJ.

3 0

2 years ago

What does frequency mean in science

matrenka [14]

There's nothing mysterious about it at all. "Frequency" simply means
"often-ness" ... how often or how frequently something happens.

-- The frequency of traditional meals is 3 per day.
-- The frequency of an equinox is 2 per year.
-- The frequency of my sleeping really late is 1 per week.
-- The frequency of my intense desire to sleep late is 30 per month.
etc.

-- The standard unit of frequency in the SI system is "per second".
The special name for that unit is "Hertz". (Hz)

6 0

3 years ago

Read 2 more answers

A person is riding a bicycle, and its wheels have an angular velocity of 10.7 rad/s. Then, the brakes are applied and the bike i

Scilla [17]

Answer:

(a) t = 22.9 s

(b) α= - 0.467 rad/s²

Explanation:

The uniformly accelerated circular movement, is a circular path movement in which the angular acceleration is constant.

We apply the equations of circular motion uniformly accelerated :

ωf ²= ω₀² + 2*α*θ Formula (1)

ωf= ω₀ + α*t Formula (2)

Where:

θ : angle that the body has rotated in a given time interval (rad)

α : angular acceleration (rad/s²)

t : time interval (s)

ω₀ : initial angular speed ( rad/s)

ωf : final angular speed ( rad/s)

Data

θ = 19.5 revolutions : angular displacement of each wheel or angle that the wheel has rotated in a given time interval

ω₀= 10.7 rad/s : initial angular speed of the Wheel ( rad/s)

ωf = 0 : final angular speed of the Whee( rad/s)

Calculating of the angular acceleration (α )

We replace data in the fómula (1),considering that 1 revolution is equal to 2π radians :

ωf ²= ω₀² + 2*α*θ

(0 )²= (10.7)² + 2*α*(19.5*2*π )

0= 114.49 + (245.04)*α

-114.49 = (245.04)*α

α= (-114.49) /(245.04)

α= -114.49 /(245.04)

α= -0.467 rad/s²

Time does it take for the bike to come to rest

We replace data in the formula (2)

ωf = ω₀ + α*t

0 = 10.7 + -0.467*t

-10.7 = - 0.467*t we multiply by (-1) both sides of the equation :

10.7 = 0.467*t

t = 10.7 / 0.467

t = 22.9 s

3 0

2 years ago

An archer pulls a bowstring back a distance of 20 cm with an average force of 75 N. The arrow has a mass of 20.0 g. When he rele

Masja [62]

To solve this problem we will apply the concepts related to the work theorem for which it is defined as the product of Force and distance. In turn, we will use the energy conservation theorem for which the applied work must be equivalent to the total kinetic energy on the body.

The work is defined as

$W = Fd$

Here,

F = Force

d = Displacement

Replacing with our values we have that

$W = 75*0.2$

$W = 15J$

Now by conservation of energy,

$W = KE$

$W = \frac{1}{2}mv^2$

$15 = \frac{1}{2} (20*10^{-3}kg)(v^2)$

Solving for v,

$v = 10\sqrt{15}$

$v = 38.72 \approx 39$

Therefore the correct answer is D.

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3 years ago

What is one major difference between the attributes of Mercury and Jupiter? A. Mercury is the planet that is closest to the Sun,

sergeinik [125]

The major difference is: Mercury has no orbiting satellites, while Jupiter has many satellites that surround it, so the correct answer is C

3 0

3 years ago

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