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4 years ago

Why were Aristotle's and Ptolemy's models were accepted for more than a thousand years in spite of being completely incorrect?

Physics

1 answer:

olganol [36]4 years ago

5 0

Answer:

Because it was a major contribution.

Explanation:

At the time people didn't really know any better, and they believed whatever people told them.

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Hey can someone help plzzzzz

ohaa [14]

Answer:

Potential Energy stored = mgh ; m : mass, g : gravitational acceleration (let 10m/s) , h : height

Hence,

Energy Stored in the ball = mgh = (2*10*4) J

= 80 Joules!

8 0

3 years ago

Read 2 more answers

What is hydrometer? Describe its use and any one type of hydrometer.

nexus9112 [7]

Answer:

An instrument for measuring the density of liquids.

Explanation:

A hydrometer is an instrument used to determine specific gravity. It operates based on the Archimedes principle that a solid body displaces its own weight within a liquid in which it floats. Hydrometers can be divided into two general classes: liquids heavier than water and liquids lighter than water.

Thermohydrometers is one type of hydrometer.

7 0

3 years ago

A 90 kg ice skater moving at 12.0 m/s on the ice encounters a region of roughed up ice with a coefficient of kinetic friction of

balandron [24]

Answer:

The skater covers a distance of <u>15 m</u> before stopping.

Explanation:

Let the distance traveled before stopping be 'd' m.

Given:

Mass of the skater (m) = 90 kg

Initial velocity of the skater (u) = 12.0 m/s

Final velocity of the skater (v) = 0 m/s (Stops finally)

Coefficient of kinetic friction (μ) = 0.490

Acceleration due to gravity (g) = 9.8 m/s²

Now, we know that, from work-energy theorem, the work done by the net force on a body is equal to the change in its kinetic energy.

Here, the net force acting on the skater is only frictional force which acts in the direction opposite to motion.

Frictional force is given as:

$f=\mu N$

Where, 'N' is the normal force acting on the skater. As there is no vertical motion, $N=mg$

∴ $f=\mu mg=0.490\times 90\times 9.8=432.18\ N$

Now, work done by friction is a negative work as friction and displacement are in opposite direction and is given as:

$W=-fd=-432.18d$

Now, change in kinetic energy is given as:

$\Delta K=\frac{1}{2}m(v^2-u^2)\\\\\Delta K=\frac{1}{2}\times 90(0-12^2)\\\\\Delta K=45\times (-144)=-6480\ J$

Therefore, from work-energy theorem,

$W=\Delta K\\\\-432.18d=6480\\\\d=\frac{6480}{432.18}\\\\d=14.99\approx 15\ m$

Hence, the skater covers a distance of 15 m before stopping.

7 0

3 years ago

If an object is rolling without slipping, how does its linear speed compare to its rotational speed?

RoseWind [281]

Answer:

v = rw

Explanation:

When an object is rolling continuously without slipping, then every angle it rotates through, is equal to a distance the perimeter has rotated.

If the object completes 10 revolutions and takes a particular time, let's say t to complete it. The angular distance would then be 20 π rad, while its angular velocity will be 20 π/t

The circumference will somehow translate to the distance it covers, which is 20πr, this means that the speed is 20πr/t

So, like the question asked, the linear speed compared to angular speed is

v : w

20πr/t : 20πt, which can be simplified to

r : 1

In essence, v = rw

3 0

4 years ago

A 2.0-Coulomb bead is given 20 Joules of electric potential energy by lifting it from the "ground" to point A. If a second bead

Katen [24]

Answer:

40 J