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Anastasy [175]
3 years ago
15

The train speeds passed Holly at 70 km/h north ward. This spider crawls past lukes foot in the same direction at 30 m/h. What is

the velocity of the spider relative to Holly?
Physics
1 answer:
konstantin123 [22]3 years ago
3 0
It has 178200000 ms^-1 and the train has 25200000ms^-1.
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A small water pump is used in an irrigation system. The pump takes water in from a river at 10oC, 100 kPa at a rate of 5 kg/s. T
sergij07 [2.7K]

Answer:

0.98kW

Explanation:

The conservation of energy is given by the following equation,

\Delta U = Q-W

\dot{m}(h_1+\frac{1}{2}V_1^2+gz_1)-\dot{W} = \dot{m}(h_2+\frac{1}{2}V_2^2+gz_)

Where

\dot{m} = Mass flow

h_1 =Specific Enthalpy (IN)

h_2 = Specific Enthalpy (OUT)

g = Gravity

z_{1,2} = Heigth state (In, OUT)

V_{1,2} =Velocity (In, Out)

Our values are given by,

T_i = 10\°C

P_1 = 100kPa

\dot{m} = 5kg/s

z_2 = 20m

For this problem we know that as pressure, temperature as velocity remains constant, then

h_1 = h_2

V_1 = V_2

Then we have that our equation now is,

\dot{m}(gz_1) = \dot{m}(gz_2)+\dot{W}

\dot{W} = \frac{(5)(9.81)(0-20)}{1000}

\dot{W} = -0.98kW

8 0
3 years ago
A catapult launches a test rocket vertically upward from a well, giving the rocket an initial speed of 80.6 m/s at ground level.
kow [346]

Before the engines fail, the rocket's altitude at time <em>t</em> is given by

y_1(t)=\left(80.6\dfrac{\rm m}{\rm s}\right)t+\dfrac12\left(3.90\dfrac{\rm m}{\mathrm s^2}\right)t^2

and its velocity is

v_1(t)=80.6\dfrac{\rm m}{\rm s}+\left(3.90\dfrac{\rm m}{\mathrm s^2}\right)t

The rocket then reaches an altitude of 1150 m at time <em>t</em> such that

1150\,\mathrm m=\left(80.6\dfrac{\rm m}{\rm s}\right)t+\dfrac12\left(3.90\dfrac{\rm m}{\mathrm s^2}\right)t^2

Solve for <em>t</em> to find this time to be

t=11.2\,\mathrm s

At this time, the rocket attains a velocity of

v_1(11.2\,\mathrm s)=124\dfrac{\rm m}{\rm s}

When it's in freefall, the rocket's altitude is given by

y_2(t)=1150\,\mathrm m+\left(124\dfrac{\rm m}{\rm s}\right)t-\dfrac g2t^2

where g=9.80\frac{\rm m}{\mathrm s^2} is the acceleration due to gravity, and its velocity is

v_2(t)=124\dfrac{\rm m}{\rm s}-gt

(a) After the first 11.2 s of flight, the rocket is in the air for as long as it takes for y_2(t) to reach 0:

1150\,\mathrm m+\left(124\dfrac{\rm m}{\rm s}\right)t-\dfrac g2t^2=0\implies t=32.6\,\mathrm s

So the rocket is in motion for a total of 11.2 s + 32.6 s = 43.4 s.

(b) Recall that

{v_f}^2-{v_i}^2=2a\Delta y

where v_f and v_i denote final and initial velocities, respecitively, a denotes acceleration, and \Delta y the difference in altitudes over some time interval. At its maximum height, the rocket has zero velocity. After the engines fail, the rocket will keep moving upward for a little while before it starts to fall to the ground, which means y_2 will contain the information we need to find the maximum height.

-\left(124\dfrac{\rm m}{\rm s}\right)^2=-2g(y_{\rm max}-1150\,\mathrm m)

Solve for y_{\rm max} and we find that the rocket reaches a maximum altitude of about 1930 m.

(c) In part (a), we found the time it takes for the rocket to hit the ground (relative to y_2(t)) to be about 32.6 s. Plug this into v_2(t) to find the velocity before it crashes:

v_2(32.6\,\mathrm s)=-196\frac{\rm m}{\rm s}

That is, the rocket has a velocity of 196 m/s in the downward direction as it hits the ground.

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3 years ago
If you drop a bowling ball, a tennis ball, and a feather from the top of a tall building at the same time which one will hit the
Whitepunk [10]
In the absence of air resistance the result is D .
6 0
3 years ago
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The sun will probably end up as a white dwarf. How will it be different then from what it is today
just olya [345]

Answer:

The differences that will be observed are;

1) The Sun will become faint and will no longer be yellow but rather appear white and will no longer be visible (become invisible) by unassisted vision as we can see the Sun today

2) The size of the Sun will shrink to a size comparable to the size of the Earth

3) The Sun will cool down and will no longer radiate as much heat

4) The nuclear reactions that generate energy on the Sun's will seize and the and the heat from the Sun will be from residual thermal energy

5) The core, which is the hottest part of the Sun will no longer be hydrogen but carbon and oxygen

Explanation:

6 0
3 years ago
Which of the following is the largest unit?<br> Hectogram<br> Dekagram<br> Decigram<br> Microgram
MAXImum [283]

Answer:

So far it seems that hectogram us the largest unit.

Dekagram is a metric unit of mass or weight, equal to 10 grams.

Hectogram is a metric unit of mass equal to 100 grams.

Decigram is  a metric unit of mass and weight equal to ¹/₁₀ gram.

Microgram is a metric unit of mass equal to one millionth of a gram.

8 0
3 years ago
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