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3 years ago

15

_______ are an especially good indicator of climate change because scientists can find clues about ancient organisms and their e

nvironments.

1 answer:

Elis [28]3 years ago

4 0

Fossils if I am not mistaken

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How high would a skater need to start on a previous incline to make it up and around a loop that is 6.1meters high?

OlgaM077 [116]

The skater need to start 7.525 meter high.

Let,

The skater need to start on a previous incline at height = h.

Mass of the skater = m

Given, height of the loop = 6.1 meter.

Radius of the loop; r = 6.1/2 meter = 3.05 meter.

Let to make it up and around a loop that is 6.1meters high, the man required minimum velocity v on the highest point of the loop.

So, centripetal force at highest point = weight of the man

⇒ mv²/r = mg

⇒ v = √(gr)

Then, potential energy of the skater at height h is = mgh.

And, minimum energy of the skater at the highest point of the loop is = potential energy + minimum kinetic energy.

= mg(2r) + 1/2 mv²

= 2mgr + 1/2 mgr

= 5/2 mgr

According to conservation of energy,

potential energy of the skater at height h = minimum energy of the skater at the highest point of the loop

⇒ mgh = 5/2 mgr

⇒ h = 5/2 r =( 5/2 )× 3.05 meter = 7.525 meter.

Hence, required height is 7.525 meter.

Learn more about energy here:

brainly.com/question/1932868

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6 0

1 year ago

List three ways in which decreasing the need to mine gold and reducing its harmful environmental effects. (Core Case Study) coul

RoseWind [281]

It’s decreasing as environmental cause osmosis

4 0

3 years ago

A 3.9 kg block is pushed along a horizontal floor by a force of magnitude 30 N at a downward angle θ = 40°. The coefficient of k

Luba_88 [7]

Answer:

The frictional force $F_{fri} =$ 6.446 N

The acceleration of the block a = 6.04 $\frac{m}{s^{2} }$

Explanation:

Mass of the block = 3.9 kg

$\theta = 40$ °

$\mu$ = 0.22

(a). The frictional force is given by

$F_{fri} = \mu R_{N}$

$R_{N} = mg \cos \theta$

$R_{N} =$ 3.9 × 9.81 × $\cos 40$

$R_{N} =$ 29.3 N

Therefore the frictional force

$F_{fri} =$ 0.22 × 29.3

$F_{fri} =$ 6.446 N

(b). Block acceleration is given by

$F_{net} = F - F_{fri}$

F = 30 N

$F_{fri}$ = 6.446 N

$F_{net}$ = 30 - 6.446

$F_{net}$ = 23.554 N

The net force acting on the block is given by

$F_{net} = ma$

23.554 = 3.9 × a

a = 6.04 $\frac{m}{s^{2} }$

This is the acceleration of the block.

8 0

2 years ago

You are creating waves in a rope by shaking your hand back and forth. Without changing the distance your hand moves, you begin t

scoundrel [369]

Answer:

<u>Amplitude - remains the same</u>

<u>Frequency - increases</u>

<u>Period - decreases</u>

<u>Velocity - remains the same.</u>

<u />

Explanation:

The amplitude of the wave remains the same since you are not changing the distance your hand moves and the amplitude of the wave depends on how much distance your hand covers while moving.

The frequency of your wave increases since now you are moving your hand more number of times in the same period i.e. your hand is moving faster in one second. So, the frequency of your wave increases.

The period is the time taken by the wave to travel a certain distance. Since your hand is now moving faster, the wave will travel faster and will take less time to cover the same distance hence, we can say that its period will decrease.

The velocity of a wave depends on the medium in which it is travelling. Your wave was previously travelling in air and the new wave is also travelling in the same medium so the velocity of the wave remains unchanged.

7 0

2 years ago

Molecular motion is a measure of the movement of the molecules in a substance. Molecular motion is substantially different betwe

scZoUnD [109]

<span>Generally speaking, the level of molecular motion is highest in gases, where molecules move around freely in space, bouncing off of each other, and lowest in solids, where molecules are bound together in a rigid structure. As such, the answer would be A; "the molecules in air move more than the molecules in wood".</span>

8 0

3 years ago

Read 2 more answers