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GalinKa [24]
3 years ago
11

A life preserver is thrown from an helicopter straight down to a person in distress. The initial velocity of the life preserver

is 1.60 m/s and it takes 2.3 s to reach the water. (a) List the knowns in this problem. (b) How high above the water was the preserver released? Note Ignore air resistance.
Physics
1 answer:
Leno4ka [110]3 years ago
6 0

Answer:29.627 m

Explanation:

Given

Initial velocity of life preserver(u) is 1.6 m/s

it takes 2.3 s to reach the water

using equation of motion

v=u+at

v=1.6+9.81\times 2.3

v=24.163 m/s

Let s be the height of life preserver

v^2-u^2=2gs

24.163^2-1.6^2=2\times 9.81\times s

s=\frac{581.29}{2\times 9.81}

s=29.627 m

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Given a force of 100 N and a acceleration of 5 m/s, what is the mass
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Answer:

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8 0
2 years ago
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A particle moves through an xyz coordinate system while a force acts on it. When the particle has the position vector r with arr
Paha777 [63]

Answer:

The question is incomplete, below is the complete question "A particle moves through an xyz coordinate system while a force acts on it. When the particle has the position vector r with arrow = (2.00 m)i hat − (3.00 m)j + (2.00 m)k, the force is F with arrow = Fxi hat + (7.00 N)j − (5.00 N)k and the corresponding torque about the origin is vector tau = (4 N · m)i hat + (10 N · m)j + (11N · m)k.

Determine Fx."

F_{x}=-1N.m

Explanation:

We asked to determine the "x" component of the applied force. To do this, we need to write out the expression for the torque in the in vector representation.

torque=cross product of force and position . mathematically this can be express as

T=r*F

Where

F=F_{x}i+(7N)j-(5N)k  and the position vector

r=(2m)i-(3m)j+(2m)k

using the determinant method to expand the cross product in order to determine the torque we have

\left[\begin{array}{ccc}i&j&k\\2&-3&2\\ F_{x} &7&-5\end{array}\right]\\\\

by expanding we arrive at

T=(18-14)i-(-12-2F_{x})j+(12+3F_{x})k\\T=4i-(-12-2F_{x})j+(12+3F_{x})k\\\\

since we have determine the vector value of the toque, we now compare with the torque value given in the question

(4Nm)i+(10Nm)j+(11Nm)k=4i-(-12-2F_{x})j+(12+3F_{x})k\\

if we directly compare the j coordinate we have

10=-(-12-2F_{x})\\10=12+2F_{x}\\ 10-12=2F_{x}\\ F_{x}=-1N.m

8 0
3 years ago
Two people push on the same door from opposite sides as shown.
tangare [24]
The correct answer is
<span>c. one person exerts more force than the other so that the forces are unbalanced.

In fact, the door is initially at rest. In order to move the door, a net force different from zero should be applied, according to Newton's second law:
</span>\sum F = ma
<span>where the term on the left is the resultant of the forces acting on the door, m is the door mass and a its acceleration.

In order to move the door, the acceleration must be different from zero. But this means that the resultant of the forces acting on it must be different from zero: this is possible only if  the forces applied by the two persons are unbalanced, i.e. one person exerts more force than the other.</span>
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3 years ago
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A man stands by a train track to watch the train car go by. Inside, a man walks through the train car eating a hot dog (the hot
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Answer:

D) 11 m/s

Explanation:

The problem asks us to calculate the velocity of the hot dog with respect to the observer stationary outside the train. This velocity is given by:

v=v_t + v_m + v_h

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v_t=+10 m/s is the velocity of the train (towards right)

v_m=+2 m/s is the velocity of the man (towards right)

v_h=-1 m/s is the velocity of the hot-dog (towards left, so we put a negative sign)

Substituting the numbers into the equation, we find

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and the positive sign means the velocity is toward right.

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how much power is radiated as a sound from a band whose intensity is 1.6x10-3 w/m2 at a distance of 12m
Vesna [10]

2.89watts.

<h3>What is meant by sound intensity?</h3>
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  • Decibels are the units used to measure sound intensity, often known as sound power or sound pressure. The decibel (dB) unit is named after Alexander Graham Bell, who also created the audiometer and the telephone. An audiometer is a tool to gauge a person's hearing capacity for various noises.
  • Our ability to measure the flow of sound energy as a time-averaged vector quantity makes sound intensity measuring an effective method. We can identify sound sources and tell direct sound from reverberant sound in a room using the characteristics of sound intensity.

How much power is radiated as a sound from a band whose intensity is 1.6x10-3 w/m2 at a distance of 12m:

Formula: I\frac{P}{4\pi r^{2} }

I=1.6x10-3 w/m2

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I\frac{P}{4\pi r^{2} }

P=I4\pi r^{2}

   =(1.6x10-3\frac{W}{m^{2} } ) (4\pi (12m)^{2} )

   =2.89watts.

To learn more about sound intensity, refer to:

brainly.com/question/17062836

#SPJ9

8 0
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