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Liula [17]
3 years ago
11

A rescue helicopter is hovering over a person whose boat has sunk. one of the rescuers throws a life preserver straight down to

the victim with an initial velocity of 1.46 m/s and observes that is takes 1.8 s to reach the water. how high above the water was the preserver released? note that the downdraft of the helicopter reduces the effects of air resistance on the falling life preserver, so that an acceleration equal to that of gravity is reasonable.
Physics
1 answer:
Helga [31]3 years ago
7 0
When the life preserver is dropped from the helicopter, the only force acting on the object is the gravitational force. This modifies the equations of motion. Thus, the working equation is written below:

h = vt + 0.5gt²
where
v is the initial velocity
g is the acceleration due to gravity equal to 9.81 m/s²
h is the height of the fall

h = (1.46 m/s)(1.8 s) + 0.5(9.81 m/s²)(1.8 s) 
h = 11.457 m
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Suppose that the speed of an electron traveling 2.0 km/s is known to an accuracy of 1 part in 105 (i.e., within 0.0010%). What i
OverLord2011 [107]

Answer: 2.89(10)^{-3} m

Explanation:

The <u>Heisenberg uncertainty principle</u> postulates that the fact each particle has a wave associated with it, imposes restrictions on the ability to determine its position and speed at the same time.  

In other words:  

It is impossible to measure simultaneously (according to quantum physics), and with absolute precision, the value of the position and the momentum (linear momentum) of a particle. Thus, in general, the greater the precision in the measurement of one of these magnitudes, the greater the uncertainty in the measure of the other complementary variable.

Mathematically this principle is written as:

\Delta x \geq \frac{h}{4 \pi m \Delta V} (1)

Where:

\Delta x is the uncertainty in the position of the electron

h=6.626(10)^{-34}J.s is the Planck constant

m=9.11(10)^{-31}kg is the mass of the electron

\Delta V is the uncertainty in the velocity of the electron.

If we know the accuracy of the velocity is 0.001\% of the velocity of the electron V=2 km/s=2000 m/s, then \Delta V is:

\Delta V=2000 m/s(0.001\%)

\Delta V=2000 m/s(\frac{0.001}{100})

\Delta V=2(10)^{-2} m/s (2)

Now, the least possible uncertainty in position \Delta x_{min} is:

\Delta x_{min}=\frac{h}{4 \pi m \Delta V} (3)

\Delta x_{min}=\frac{6.626(10)^{-34}J.s}{4 \pi (9.11(10)^{-31}kg) (2(10)^{-2} m/s)} (4)

Finally:

\Delta x_{min}=2.89(10)^{-3} m

5 0
3 years ago
Scientists track _________________ to be able to predict geomagnetic storms and technological disturbances on Earth
Misha Larkins [42]
A. Sunspots and solar storms
6 0
3 years ago
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A spring whose stiffness is 980 N/m has a relaxed length of 0. 50 m. If the length of the spring changes from 0. 25 m to 0. 81 m
Gelneren [198K]

151.9j

Explanation:

PE=1/2kx^2

PE=1/2(980)(.50)= 245j

PE=(1/2)(980)(.81)= 396.9j

396.9- 245= 151.9j

8 0
2 years ago
The resultant of two forces acting on the same point simultaneously will be the greatest when the angle between them is:a) 180 d
r-ruslan [8.4K]

Answer:

0 degrees

Explanation:

Let F_1\ and\ F_2 are two forces. The resultant of two forces acting on the same point is given by :

F_R=\sqrt{F_1^2+F_2^2+2F_1F_2\ cos\theta}

Where \theta is the angle between two forces

When \theta=0 i.e. when two forces are parallel to each other,

F_R=\sqrt{F_1^2+F_2^2+2F_1F_2\ cos(0)}

F_R=\sqrt{F_1^2+F_2^2+2F_1F_2}

When \theta=90^{\circ} i.e. when two forces are parallel to each other,

F_R=\sqrt{F_1^2+F_2^2+F_1F_2\ cos(90)}

F_R=\sqrt{F_1^2+F_2^2}

When \theta=180^{\circ} i.e. when two forces are parallel to each other,

F_R=\sqrt{F_1^2+F_2^2+F_1F_2\ cos(180)}

F_R=\sqrt{F_1^2+F_2^2-2F_1F_2}

It is clear that the resultant of two forces acting on the same point simultaneously will be the greatest when the angle between them is 0 degrees. Hence, this is the required solution.

8 0
3 years ago
A 10 ohm and 5 ohm resistor are connected in parallel. With a current of 1.3 A in
KiRa [710]

Use formula of resistance for Parallel circuit

(refer to photo)

V = I * R

Voltage = Current * Resistance

I hope this helped.

3 0
3 years ago
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