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3 years ago

14

3 Magnetised mineral ore was found in

1 answer:

GalinKa [24]3 years ago

3 0

Answer:

D Magnesia

Explanation:

Ore particles Fe3O4 (magnetite) were found in the region called Magnesia.

Magnesia was an antic city in Asia, named after the inhabitants of Greek Magnesia.

Magnetite is used as an ore, abrasive, in paint production, electrophotography, as a micronutrient fertilizer, and as a high-density concrete aggregate.

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A question is scientific if you can answer it using which of the following?

pav-90 [236]

C. Observations and measurements

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3 years ago

Plzz help! A stationary speed gun emits a

baherus [9]

Answer:

The speed of the baseball is approximately 19.855 m/s

Explanation:

From the question, we have;

The frequency of the microwave beam emitted by the speed gun, f = 2.41 × 10¹⁰ Hz

The change in the frequency of the returning wave, Δf = +3190 Hz higher

The Doppler shift for the microwave frequency emitted by the speed gun which is then reflected back to the gun by the moving baseball is given by 2 shifts as follows;

$\dfrac{\Delta f}{f} = \dfrac{2 \cdot v_{baseball}}{c}$

$\therefore{\Delta f}{} = \dfrac{2 \cdot v_{baseball}}{c} \times f$

Where;

Δf = The change in frequency observed, known as the beat frequency = 3190 Hz

$v_{baseball}$ = The speed of the baseball

c = The speed of light = 3.0 × 10⁸ m/s

f = The frequency of the microwave beam = 2.41 × 10¹⁰ Hz

By plugging in the values, we have;

$\therefore{\Delta f} = 3190 \ Hz = \dfrac{2 \cdot v_{baseball}}{3.0 \times 10^8 \ m/s} \times 2.41 \times 10^{10} \ Hz$

$v_{baseball} = \dfrac{3190 \ Hz \times 3.0 \times 10^8 \ m/s }{2.41 \times 10^{10} \ Hz \times 2} \approx 19.855 \ m/s$

The speed of the baseball, $v_{baseball}$ ≈ 19.855 m/s

3 0

3 years ago

A car is moving with speed 60 m/s and acceleration 4 m/s2 at a given instant. (a) using a second-degree taylor polynomial, estim

pantera1 [17]

Answer:

Explanation:

Using second degree taylor polynomials

let $S(t)$ be position function and set $S(0)=0$

where S(0) is the initial position

Then $v(t) = S^i(t)$ and $a(t)=S^{ii}(t)$

we have $v(0) = 60m/s$ , $a(0) = 4m/s^2$

so $T_{2}(t) =S(0)+v(0)t+\frac{a(0)}{2} t^2\\\\\\=0+60t+\frac{4}{2} t^2\\\\T_{2}(t)=60t+2t^2\\\\S(1)=T_{2}(1)=60+2=62m$

b.) yes

6 0

3 years ago

A steel bridge is 1000 m long at -20°C in winter. What is the change in length when the temperature rises to 40°C in summer? The

xenn [34]

Answer:

ΔL = 0.66 m

Explanation:

The change in length on an object due to rise in temperature is given by the following equation of linear thermal expansion:

ΔL = αLΔT

where,

ΔL = Change in Length of the bridge = ?

α = Coefficient of linear thermal expansion = 11 x 10⁻⁶ °C⁻¹

L = Original Length of the Bridge = 1000 m

ΔT = Change in Temperature = Final Temperature - Initial Temperature

ΔT = 40°C - (-20°C) = 60°C

Therefore,

ΔL = (11 x 10⁻⁶ °C⁻¹)(1000 m)(60°C)

<u>ΔL = 0.66 m</u>

6 0

4 years ago

what is the mechanical advantage of a crowbar when a worker uses 10N of force to pry open a window that has a resistance of 500N

Oksana_A [137]

Answer:

50

Explanation:

The mechanical advantage of a machine is given by

$MA=\frac{F_{out}}{F_{in}}$

where

$F_{out}$ is the output force

$F_{in}$ is the input force

For the crowbar in this problem,

$F_{in}=10 N$ is the force in input applied by the worker

$F_{out}=500 N$ is the force that the machine must apply in output to overcome the resistance of the window and to open it

Substituting into the equation, we find

$MA=\frac{500}{10}=50$

3 0

4 years ago

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