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Using this information...

Pepsi [2]

$19.2\:\text{m/s}$

Explanation:

At the top of the tree, the velocity of the pebble is purely horizontal so we can calculate it as

$v_{y} = v_{0y} = v_0\cos 40° = (25\:\text{m/s})(0.766)$

$\:\:\:\:\:= 19.2\:\text{m/s}$

6 0

2 years ago

How did astronomers precisely determine the length of an Astronomical Unit in the 1960s?

zaharov [31]

Answer:

Use of telemetry and radar astronomy

Explanation:

An astronomical Unit (AU) is a unit of measuring distances in outer space, which is based on the approximate distance between the earth and the Sun.

After several years of trying to approximate the distance between the Sun and the Earth using several methods based on geometry and some other calculations, advancements in technology made available the presence of special motoring equipment, which can be placed in outer space to remotely monitor and measure the position of the sun.

The use of direct radar measurements to the sun (radar astronomy) have also made the determination of the AU more accurate.

A standard radar pulse of known speed is sent to the Sun, and the time with which it takes to return is measured, once this is recorded, the distance between the Earth and the Sun can be calculated using

distance = speed X time.

However, most of these means have to be corrected for parallax errors

5 0

2 years ago

How does the input distance of a third-class lever compare to the output distance

Alexandra [31]

Answer:

A first-class lever: fulcrum is between input and output force; second-class lever: output force is between input force and fulcrum; third-class lever: input force is between fulcrum and output force

4 0

2 years ago

Please help asdfghjkll

lara [203]

Answer:

1. B

2. B

Explanation:

1. he was the only teacher at that time that figured out that everything doesn't revolve around us. he figured it out by a telscope he made from three lens and a tube. its actually pretty cool. He found out that venus first was in front of us.

2. if the earth wasn't at a tilt, then we wouldn't have sessons, when the earth rotate around the sun, the earth is roataing at a title axis. and that changes our seesons, because if we are in south america, and we are in winter time, and south america is cold, then it means that the continent is not getting as much heat from the sun. Does that makes since, because it doesn't sound like it?

7 0

2 years ago

A simple pendulum is used to determine the acceleration due to gravity at the surface of a planet. The pendulum has a length of

Dafna1 [17]

Answer:

- pendulum use to determine acceleration

Explanation:

by calculating need to understand first the problem

the length is measure to be 2s

the lenght is also 2

2 obtainer on invistigation the most nearly is 8.

5 0

2 years ago