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3 years ago

What information can scientists obtian from tree rings

Physics

1 answer:

Alexandra [31]3 years ago

5 0

What information can scientists obtain from tree rings?

Answer's <u>I chose</u>:

<h3>how narrow the rings are</h3><h3>how the climate changed in the tree’s life</h3><h3>how wide the rings are</h3>

Please <u>correct</u> me if there are <em>more </em>or <em>less</em>

Please give a brainliest and a thanks.

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imagine you are a teacher of a science class. a student brings in a newspaper article that claims the world will run out of ener

attashe74 [19]

My opinion is that energy is not something that's made just like u feed ur self and u have energy u have to feed the earth and it will survive

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2 years ago

A tradesman sharpens a knife by pushing it with a constant force against the rim of a grindstone. The 30-cm-diameter stone is sp

Lorico [155]

Answer:

a. 0.21 rad/s2

b. 2.205 N

Explanation:

We convert from rpm to rad/s knowing that each revolution has 2π radians and each minute is 60 seconds

200 rpm = 200 * 2π / 60 = 21 rad/s

180 rpm = 180 * 2π / 60 = 18.85 rad/s

r = d/2 = 30cm / 2 = 15 cm = 0.15 m

a)So if the angular speed decreases steadily (at a constant rate) from 21 rad/s to 18.85 rad/s within 10s then the angular acceleration is

$\alpha = \frac{\Delta \omega}{\Delta t} = \frac{21 - 18.85}{10} = 0.21 rad/s^2$

b) Assume the grind stone is a solid disk, its moment of inertia is

$I = mR^2/2$

Where m = 28 kg is the disk mass and R = 0.15 m is the radius of the disk.

$I = 28*0.15^2/2 = 0.315 kgm^2$

So the friction torque is

$T_f = I\alpha = 0.315*0.21 = 0.06615 Nm$

The friction force is

$F_f = T_f/R = 0.06615 / 0.15 = 0.441 N$

Since the friction coefficient is 0.2, we can calculate the normal force that is used to press the knife against the stone

$N = F_f/\mu = 0.441/0.2 = 2.205 N$

7 0

3 years ago

Which three metal do you think might be present in alnico explain ? ans which one are magnetic

erma4kov [3.2K]

Answer:

Aluminium, Nickel, Cobalt and Iron plus varying levels of Copper, Titanium and Niobium.

MAGNETIC: Alni, Alcomax, Hycomax, Columax, and Ticonal.

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3 years ago

In an area in which electricity costs 8 cents/kilowatt-hour, a 5 kW clothes dryer runs for 90 minutes to dry a load of laundry.

Over [174]

$0.60
90 mins is 1.5 hrs
5 kW × 1.5 = 7.5 kWh
7.5 kWh × $0.08 = $0.60

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2 years ago

Read 2 more answers

Which energy transformation occurs in the core of a nuclear reactor?

romanna [79]

The correct answer among the choices given is option B. The energy transformation that occurs in the core of a nuclear reactor is from nuclear energy to thermal energy. In a power plant nuclear fission which involves nuclear energy to heat up water around it. This part is the core of the process.

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3 years ago