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3 years ago

11

A spinning ice skater will slow down if she extends her arms away from her body. Which of the following statements explains this

phenomenon?

1 answer:

klasskru [66]3 years ago

6 0

Drag from her armas would slow her down if she was spinning at a fast speed

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What do radio waves and microwaves have in common?

Tamiku [17]

Answer:

I Will say the Answer is A

Explanation:

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2 years ago

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A van is traveling with an initial velocity of 12 m/s. The driver takes a time of 45 seconds to speed up to a velocity of 20 m/s

Rufina [12.5K]

Initial velocity=u=12m/s
Final velocity=v=20m/s
Time=t=45s

$\\ \rm\hookrightarrow Acceleration=\dfrac{v-u}{t}$

$\\ \rm\hookrightarrow Acceleration=\dfrac{20-12}{45}$

$\\ \rm\hookrightarrow Acceleration=\dfrac{8}{45}$

$\\ \rm\hookrightarrow Acceleration=0.1m/s^2$

Now

Distance=s

$\\ \rm\hookrightarrow v^2-u^2=2as$

$\\ \rm\hookrightarrow (20)^2-12^2=2(0.1)s$

$\\ \rm\hookrightarrow 400-144=0.2s$

$\\ \rm\hookrightarrow 256=0.2s$

$\\ \rm\hookrightarrow s=\dfrac{256}{0.2}$

$\\ \rm\hookrightarrow s=1280m$

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2 years ago

You are asked to design a cylindrical steel rod 50.0 cm long, with a circular cross section, that will conduct 170.0 J/s from a

zepelin [54]

Answer:

You are asked to design a cylindrical steel rod 50.0 cm long, with a circular cross section, that will conduct 170.0 J/s from a furnace at 350.0 ∘C to a container of boiling water under 1 atmosphere.

Explanation:

Given Values:

L = 50 cm = 0.5 m

H = 170 j/s

To find the diameter of the rod, we have to find the area of the rod using the following formula.

Here Tc = 100.0° C

k = 50.2

H = k × A × $\frac{[T_{H -}T_{C} ] }{L}$

Solving for A

A = $\frac{H * L }{k * [ T_{H}- T_{C} ] }$

A = $\frac{170 * 0.5}{50.2 * [ 350 - 100 ]}$

A = $\frac{85}{12550}$ = 6.77 × $10^{-3}$ m²

Now Area of cylinder is :

A = $\frac{\pi }{4}$ d²

solving for d:

d = $\sqrt{\frac{4 * 0.00677 }{\pi } }$

d = 9.28 cm

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3 years ago

Suppose you are planning a trip in which a spacecraft is to travel at a constant velocity for exactly six months, as measured by

bixtya [17]

Answer:

v = 0.99 c = 2.99 x 10⁸ m/s

Explanation:

From the special theory of relativity:

$t = \frac{t_o}{\sqrt{1-\frac{v^2}{c^2} } }\\$

where,

v = speed of travel = ?

c = speed of light = 3 x 10⁸ m/s

t = time measured on earth = 90 years

t₀ = time measured in moving frame = 6 months = 0.5 year

Therefore,

$90\ yr = \frac{0.5\ yr}{\sqrt{1-\frac{v^2}{c^2} } } \\\\\\\sqrt{1-\frac{v^2}{c^2}} = \frac{0.5\ yr}{90\ yr}\\ 1-\frac{v^2}{c^2} = 0.00003086\\\frac{v^2}{c^2} = 1-0.00003086\\$

<u>v = 0.99 c = 2.99 x 10⁸ m/s</u>

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3 years ago

Convert 1.3 km to m

a_sh-v [17]

Answer: 1300m

Explain: from km to m times 1000

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2 years ago