3 years ago

Why do stars seem to move at night? ght

Physics

2 answers:

frez [133]3 years ago

5 0

Answer:

it because the earth rotates slowly on it's axis which causes day and night

Tema [17]3 years ago

4 0

It looks that way cause the earth is rotation on its axis

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What situation would give you a mechanical advantage? *

const2013 [10]

D. Using a fixed-pulley system

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3 years ago

a 230 kg roller coaster reaches the top of the steepest hill with a speed of 6.2 km/h. It then descends the hill, which is at an

igor_vitrenko [27]

Answer: 81.619 kJ

Explanation:

Given

Mass of roller coaster is $m=230\ kg$

It reaches the steepest hill with speed of $u=6.2\ km/h\ or \ 1.72\ m/s$

Hill to bottom is 51 m long with inclination of $45^{\circ}$

Height of the hill is $h=51\sin 45^{\circ}=36.06\ m$

Conserving energy to get kinetic energy at bottom

Energy at top=Energy at bottom

$\Rightarrow K_t+U_t=K_b+U_b\\\Rightarrow \dfrac{1}{2}mu^2+mgh=K_b+0\\\\\Rightarrow K_b=0.5\times 230\times 1.72^2+230\times 9.8\times 36.06\\\Rightarrow K_b=340.216+81,279.24\\\Rightarrow K_b=81,619.456\ J\\\Rightarrow K_b=81.619\ kJ$

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2 years ago

An airplane travels 4000m in 16 seconds on a heading of 35 whats is its velocity

Marizza181 [45]

In the question, you just gave a complete and detailed
description of the plane's velocity vector:

4,000/16 meters/second , heading 35 degrees .

You might want to simplify the speed and make it a unit rate,
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3 years ago

Which point or points of view could be present in a business letter?

Studentka2010 [4]

Answer:

Explanation:

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3 years ago

A diver springs upward from a board that is 2.70 m above the water. At the instant she contacts the water her speed is 10.9 m/s

TiliK225 [7]

Answer:

vo=5.87m/s

Explanation:

Hello! In this problem we have a uniformly varied rectilinear movement.

Taking into account the data:

α =69.2

vf = 10m / s

h=2.7m

g=9.8m/s2

We know we want to know the speed on the y axis.

We calculate vfy

vfy = 10m / s * (sen69.2) = 9.35m / s

We can use the following equation.

$vf^{2} =vo^{2}+2*g*h\\$

We clear the vo (initial speed)

$vo=\sqrt{vf^{2}-2*g*h }$

$v0=\sqrt{(9.35m/s)^{2}-2*9.8m/s^{2} *2.7m}$

vo=5.87m/s

7 0

2 years ago