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3 years ago

1. Magnetism comes from ____________________ inside the Earth.

Physics

1 answer:

olya-2409 [2.1K]3 years ago

5 0

Answer:

1. Magnetism comes from minerals found inside the Earth.

2. Iron, nickel, and cobalt does stick to magnets.

3. Moving electrons can produce electricity to make a magnet.

4. A compass works because Earth is magnetic.

5. In a magnet, the electrons are in a line.

6. A magnet has a north and south pole.

7. Two north poles will push away from each other.

8. An MRI is a test that uses magnets to see inside of the brain.

9. The Earth’s core is iron and nickel.

10. The north pole and south pole of a magnet attracts.

11. A magnetic field is formed when electricity is flowing.

12. When a compass faces north it is called a magnetic field.

13. Aurora Borealis are the solarwinds glowing at the North Pole.

14. Sunspots are caused by the sun’s magnetic field.

15. In a computer, the __________________________ chips are magnetic

Explanation:

In my class we watched "Bill Nye the Science Guy S02E01 Magnetism" first video that shows up

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Careful measurements have been made of Olympic sprinters in the 100-meter dash. A quite realistic model is that the sprinter's v

mihalych1998 [28]

Answer:

$\displaystyle a(0 )=8.133\ m/s^2$

$\displaystyle a(2)=2.05\ m/s^2$

$\displaystyle a(4)=0.52\ m/s^2$

b. $\displaystyle X(t)=11.81(t+1.45\ e^{-0.6887t})-17.15$

c. $t=9.9 \ sec$

Explanation:

Modeling With Functions

Careful measurements have produced a model of one sprinter's velocity at a given t, and it's is given by

$\displaystyle V(t)=a(1-e^{bt})$

For Carl Lewis's run at the 1987 World Championships, the values of a and b are

$\displaystyle a=11.81\ ,\ b=-0.6887$

Please note we changed the value of b to negative to make the model have sense. Thus, the equation for the velocity is

$\displaystyle V(t)=11.81(1-e^{-0.6887t})$

a. What was Lewis's acceleration at t = 0 s, 2.00 s, and 4.00 s?

To compute the accelerations, we must find the function for a as the derivative of v

$\displaystyle a(t)=\frac{dv}{dt}=11.81(0.6887\ e^{0.6887t})$

$\displaystyle a(t)=8.133547\ e^{-0.6887t}$

For t=0

$\displaystyle a(0)=8.133547\ e^o$

$\displaystyle a(0 )=8.133\ m/s^2$

For t=2

$\displaystyle a(2)=8.133547\ e^{-0.6887\times 2}$

$\displaystyle a(2)=2.05\ m/s^2$

$\displaystyle a(4)=8.133547\ e^{-0.6887\times 4}$

$\displaystyle a(4)=0.52\ m/s^2$

b. Find an expression for the distance traveled at time t.

The distance is the integral of the velocity, thus

$\displaystyle X(t)=\int v(t)dt \int 11.81(1-e^{-0.6887t})dt=11.81(t+\frac{e^{-0.6887t}}{0.6887})+C$

$\displaystyle X(t)=11.81(t+1.45201\ e^{-0.6887t})+C$

To find the value of C, we set X(0)=0, the sprinter starts from the origin of coordinates

$\displaystyle x(0)=0=>11.81\times1.45201+C=0$

Solving for C

$\displaystyle c=-17.1482\approx -17.15$

Now we complete the equation for the distance

$\displaystyle X(t)=11.81(t+1.45\ e^{-0.6887t})-17.15$

c. Find the time Lewis needed to sprint 100.0 m.

The equation for the distance cannot be solved by algebraic procedures, but we can use approximations until we find a close value.

We are required to find the time at which the distance is 100 m, thus

$\displaystyle X(t)=100=>11.81(t+1.45\ e^{-0.6887t})-17.15=100$

Rearranging

$\displaystyle t+1.45\ e^{-0.6887t}=9.92$

We define an auxiliary function f(t) to help us find the value of t.

$\displaystyle f(t)=t+1.45\ e^{-0.687t}-9.92$

Let's try for t=9 sec

$\displaystyle f(9)=9+1.45\ e^{-0.687\times 9}-9.92=-0.92$

Now with t=9.9 sec

$\displaystyle f(9.9)=9.9+1.45\ e^{-0.687\times 9.9}-9.92=-0.0184$

That was a real close guess. One more to be sure for t=10 sec

$\displaystyle f(10)=10+1.45\ e^{-0.687\times 10}-9.92=0.081$

The change of sign tells us we are close enough to the solution. We choose the time that produces a smaller magnitude for f(t).

$At t\approx 9.9\ sec, \text{ Lewis sprinted 100 m}$

7 0

3 years ago

A man is standing on the edge of a 20.0 m high cliff. He throws a rock horizontally with an initial velocity of 10.0 m/s. How lo

Arlecino [84]

Answer:

t = 4.08 s

R = 40.8 m

Explanation:

The question is asking us to solve for the time of flight and the range of the rock.

Let's start by finding the total time it takes for the rock to land on the ground. We can use this constant acceleration kinematic equation to solve for the displacement in the y-direction:

Δx = v_0 t + 1/2at²

We have these known variables:

(v_0)_y = 0 m/s
a_y = -9.8 m/s²
Δx_y = -20 m

And we are trying to solve for t (time). Therefore, we can plug these values into the equation and solve for t.

-20 = 0t + 1/2(-9.8)t²
-20 = 1/2(-9.8)t²
-20 = -4.9t²
t = 4.08 sec

The time it takes for the rock to reach the ground is 4.08 seconds.

Now we can use this time in order to solve for the displacement in the x-direction. We will be using the same equation, but this time it will be in terms of the x-direction.

List out known variables:

v_0 = 10 m/s
t = 4.08 s
a_x = 0 m/s

We are trying to solve for:

Δx_x = ?

By using the same equation, we can plug these known values into it and solve for Δx.

Δx = 10 * 4.08 + 1/2(0)(4.08)²
Δx = 10 * 4.08
Δx = 40.8 m

The rock lands 40.8 m from the base of the cliff.

7 0

3 years ago

Sound waves need a medium to move through in order to keep moving. Through which of the following would sound travel the slowest

Troyanec [42]

Answer:A air

Explanation:Of the three mediums (gas, liquid, and solid) sound waves travel the slowest through gases, faster through liquids, and fastest through solids. Temperature also affects the speed of sound.

Hope this helps you out ツ

8 0

3 years ago

Read 2 more answers

You will measure and record the time it takes the cart to travel certain distances, and then complete some calculations. In the

natka813 [3]

Answer:

Take the measurement of the distance (d) with a meter rule (in meters) and also measure the time (t) of the travel in seconds with a stopwatch.

question: What is the speed of the cart?

Explanation:

The speed of an object in motion is the distance covered by the object with respect to time, that is, the ratio of distance covered to the time taken to reach that distance.

Speed = distance / time

= d (in meters m) / t (in seconds s) = m/s

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3 years ago

HELPPP PLS BESTIES A pattern of stars that has been named is called a constellation. One winter evening, Jason found the star ca

Damm [24]

Answer:

D) Since the stars would move from East to West just as the Sun and Moon do.

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3 years ago