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3 years ago

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A roller coaster starts from rest at its highest point and then descends on its (frictionless) track. Its speed is 38 m/s when i

t reaches ground level. What was its speed when its height was half that of its starting point

1 answer:

inysia [295]3 years ago

5 0

Explanation:

look !

speed= 38m/s

start from rest= 0

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You work for the city water department and need to pump 3400 liters/minute of water from a tank at ground level into a vented (i

umka21 [38]

Answer:

$P_E=46.2778\ kW$

$v=1.804\ m.s^{-1}$

Explanation:

Given:

flow rate of water, $\dot{V}=3400\ L.min^{-1}=3.4\ m^3.min^{-1}$

<em>∵Density of water is 1 kg per liter</em>

∴mass flow rate of water, $\dot{m}=3400\ kg.min^{-1}$

height of pumping, $h=75\ m$

efficiency of motor drive, $\eta=0.9$

diameter of pipe, $D =0.2\ m$

<u>Now the power required for pumping the water at given conditions:</u>

$P=\dot{m}.g.h$

$P=\frac{3400}{60} \times 9.8\times 75$

$P=41650\ W$

<u>Hence the electric power required:</u>

$P_E \times \eta=P$

$P_E \times 0.9=41650$

$P_E=46.2778\ kW$

<u>Flow velocity is given as:</u>

$v=\dot{V}\div a$

where: a = cross sectional area of flow through the pipe

$v=\frac{3.4}{60}\div (\pi.\frac{0.2^2}{4} )$

$v=1.804\ m.s^{-1}$

3 0

3 years ago

Which example possesses mechanical potential energy?. A. a taut guitar string. B. an oscillating pendulum. C. a roller coaster r

Andrej [43]

<span>
The taut guitar string haspotencial energy which we can see in action.</span> <span>· so option a is correct.</span>

6 0

3 years ago

Read 2 more answers

1. How many paths through which charge can flow would be shown in a diagram of a series

Elanso [62]

1. One
2. Oohm

Hope this helps

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3 years ago

Water can be used to create electricity. this type of energy is called _____. nuclear power hydroelectric power electrolysis cur

ioda

Hydroelectric power. That's just the term for electricity gained by using water, think of a water mill.

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3 years ago

An electron moves with velocity v⃗ =(5.8i−6.7j)×104m/s in a magnetic field B⃗ =(−0.81i+0.60j)T.

Minchanka [31]

Answer:

Fₓ = 0, $F_{y}$ = 0 and $F_{z}$ <em> = - 3.115 10⁻¹⁵ N</em>

Explanation:

The magnetic force given by the expression

F = q v xB

the bold are vectors, the easiest analytical way to determine this force in solving the determinant

$F = q \left[\begin{array}{ccc}i&j&k\\5.8&-6.7&0\\-0.81&0.6&0\end{array}\right] 10^{4}$

F = 1.6 10⁻¹⁵ [ i( 0-0) + j (0-0) + k^( 5.8 0.60 - 0.81 67) ]

F =i^0 + j^0 - k^ 3.115 10⁻¹⁵ N

Fₓ = 0

$F_{y}$ = 0

$F_{z}$ <em> = - 3.115 10⁻¹⁵ N</em>

6 0

3 years ago