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3 years ago

Alex collides with a desk as he runs through his office. If the combined

Physics

2 answers:

Ivan3 years ago

8 0

Answer:

400 kg.m/s

Explanation:

In a closed system, the principle of conservation of momentum applies. It means. the total momentum before collision equals to the total momentum after collision hence since the initial momentum is given as 400 kg.m/s, the final sum will be the same.

Alexus [3.1K]3 years ago

8 0

Answer:

400 kg•m/s north

Explanation:

answer for quiz from apex

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Please help! Will give brainliest.

I am Lyosha [343]

<span>The correct frequency when you tune a guitar is when you hear the right tune in your own hearing and standard. The measure frequency of a guitar string is when you measure the tune of the string correctly. This is not the same because manual tuning is affected by many factors.</span>

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4 years ago

A 4 kg rock is dropped from 5 m. There is no friction. What kind of energy does is have before? What kind of energy does it have

denpristay [2]

1) The total mechanical energy of the rock is:
$E=U+K$
where U is the gravitational potential energy and K the kinetic energy.

Initially, the kinetic energy is zero (because the rock starts from rest, so its speed is zero), and the total mechanical energy of the rock is just gravitational potential energy. This is equal to
$E_i=U=mgh$
where $m=4 kg$ is the mass, $g=9.81 m/s^2$ is the gravitational acceleration and $h=5 m$ is the height.
Putting the numbers in, we find the potential energy
$U=mgh=(4 kg)(9.81 m/s^2)(5 m)=196.2 J$

2) Just before hitting the ground, the potential energy U is zero (because now h=0), and all the potential energy of the rock converted into kinetic energy, which is equal to:
$E_f=K= \frac{1}{2}mv^2$
where v is the speed of the rock just before hitting the ground. Since the mechanical energy of the rock must be conserved, then the kinetic energy K before hitting the ground must be equal to the initial potential energy U of the rock:
$K=U=196.2 J$

3) For the work-energy theorem, the work W done by the gravitational force on the rock is equal to the variation of kinetic energy of the rock, which is:
$W=196.2 J-0 J=196.2 J$

6 0

3 years ago

The howler monkey is the loudest land animal and, under some circumstances, can be heard up to a distance of 8.9 km. Assume the

Airida [17]

Answer:

$\frac{I}{I_0}=113.68$

Explanation:

P = Acoustic power = 63 µW

r = Distance to the sound source = 210 m

Acoustic power

$P=IA\\\Rightarrow I=\frac{P}{A}\\\Rightarrow I=\frac{63\times 10^{-6}}{4\times \pi \times 210^2}$

Threshold intensity = $I_0=1\times 10^{-12}\ W/m^2$

Ratio

$\frac{I}{I_0}=\frac{\frac{63\times 10^{-6}}{4\times \pi \times 210^2}}{1\times 10^{-12}}\\\Rightarrow \frac{I}{I_0}=113.68$

Ratio of the acoustic intensity produced by the juvenile howler to the reference intensity is 113.68

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3 years ago

The gamma ray released by each decay carries 140kev of energy. find the total energy e released by decays in the 2 hours.

olya-2409 [2.1K]

First, we would need to know the decaying isotope.
Next, we use the decay formula
A = Ao e^(-kt)
After determining the remaining amount after two hours, the decay reaction can be used to determine the number of gamma rays released. If the given is in terms of mole, then the total energy is
E = 140n KeV where n is the number of moles of gamma rays released

8 0

3 years ago

Read 2 more answers

A 1.5m wire carries a 7 A current when a potential difference of 68 V is applied. What is the resistance of the wire?

PSYCHO15rus [73]

Working...

length of wire L = 1.5 m

current I = 7 A

potential difference V = 68 Volt

According to Ohm's Law

V = IR

R = V/I

R = 68/7

R = 9.7 Ω

3 0

4 years ago