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3 years ago

14

a stationary police officer directs radio waves emitted by a radar gun at a vehicle toward the officer. Compared to the emitted

radio waves, the radio waves reflected from the vehicle and received by the radar gun have a A.) longer wavelength B.) higher speed C.) longer period D.) higher frequency

1 answer:

Arisa [49]3 years ago

3 0

Answer:

D) Higher Frequency

Explanation:

Higher frequency because it says a vehicle “towards” the officer

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The alpha line in the balmer series of the hydrogen spectrum consists of light having a wavelength of 6.56. calculate the freque

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The alpha line in the Balmer series is the transition from n=3 to n=2 and with the wavelength of λ=656 nm = 6.56*10^-7 m. To get the frequency we need the formula: v=λ*f where v is the speed of light, λ is the wavelength and f is the frequency, or c=λ*f. c=3*10^8 m/s. To get the frequency: f=c/λ. Now we input the numbers: f=(3*10^8)/(6.56*10^-7)=4.57*10^14 Hz. So the frequency of the light from alpha line is f= 4.57*10^14 Hz.

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3 years ago

A 10 kg turkey, He kicks the 0.5 kg ball with a force of 50N for 0.2 seconds and the ball flies straight away horizontally from

Harman [31]

Answer:

a. 20m/s

b.50N

c. Turkey has a larger mass than the ball. Neglible final acceleration and therefore remains stationery.

Explanation:

a. Given the force as 50N, times as 0.2seconds and the weight of the ball as 0.5 kg, it's final velocity can be calculated as:

$F\bigtriangleup t=m\bigtriangleup v\\\\50N\times 0.2s=0.5kg\times \bigtriangleup v\\\\\bigtriangleup v=2(50N\times0.2)\\\\=20m/s$

Hence, the velocity of the ball after the kick is 20m/s

b.The force felt by the turkey:

#Applying Newton's 3rd Law of motion, opposite and equal reaction:

-The turkey felt a force of 50N but in the opposite direction to the same force felt by the ball.

c. Using the law of momentum conservation:

-Due to ther external forces exerted on the turkey, it remains stationery.

-The turkey has a larger mass than the ball. It will therefore have a negligible acceleration if any and thus remains stationery.

-Momentum is not conserved due to these external forces.

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3 years ago

HELP ASAP ILL GIVE BRAINLIST

OlgaM077 [116]

Answer:

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2 years ago

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A machine part has the shape of a solid uniform sphere of mass 250 g and a diameter of 4.30 cm. It is spinning about a frictionl

zysi [14]

Answer: $\alpha =9.302\ rad/s^2$

Explanation:

Given

mass of sphere $m=250\ gm$

diameter of sphere $d=4.30\ cm$

radius $r=\frac{4.30}{2}\ cm$

$f=0.0200\ N$

friction will provide resisting torque so

$f\times r=I\times \alpha$

where $I=\text{moment of Inertia}$

$f=\text{friction force}$

$\alpha =\text{angular acceleration}$

$I=\frac{2}{5}mr^2$

$0.02\times r=\frac{2}{5}mr^2\times \alpha$

$\alpha =\frac{5}{2r}\times f$

$\alpha =\frac{5}{2}\times \frac{2}{4.3\times 10^{-2}}\times 0.02$

$\alpha =9.302\ rad/s^2$

(b)time taken to decrease its rotational speed by $21\ rad/s$

$t=\dfrac{\Delta \omega }{\alpha }$

$t=\dfrac{21}{9.302}$

$t=2.25\ s$

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3 years ago

In 2013, the world record depth for free diving without assistance was 101 m. What is the pressure in the water (assumed freshwa

serg [7]

Answer:

The pressure in the water is $1.1\times10^{6}\ Pa$

Explanation:

Given that,

Depth = 101 m

Let P be the pressure at the bottom of water at a depth

We need to calculate the pressure in water

Using formula of pressure

$P=P_{w}+P_{atm}$

Where, $P_{atm}$ = atmospheric pressure

$P_{w}$ = pressure in water

Put the value of $P_{w}$ in to the formula

$P=\rho hg+P_{atm}$

Put the value into the formula

$P=1000\times101\times9.8+101325$

$P=1.1\times10^{6}\ Pa$

Hence, The pressure in the water is $1.1\times10^{6}\ Pa$

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2 years ago

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