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3 years ago

PLEASE HELP, I don’t know how to do this

Physics

1 answer:

MrRa [10]3 years ago

7 0

Explanation:

7) Given:

v₀ = 2.0 m/s

v = 0 m/s

t = 3.00 s

Find: Δx

Acceleration isn't included in the problem, so use a kinematic equation that doesn't involve a.

Δx = ½ (v + v₀) t

Δx = ½ (0 m/s + 2.0 m/s) (3.00 s)

Δx = 3.0 m

8) Given:

v₀ = 0 m/s

v = 5 m/s

t = 4 s

Find: a

Displacement isn't included in the problem, so use a kinematic equation that doesn't involve Δx.

v = at + v₀

5 m/s = a (4 s) + 0 m/s

a = 1.25 m/s²

9) Given:

v_avg = Δx / t

0.5 m/s = 8 m / t

t = 16 s

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A submarine is stranded on the bottom of the ocean with its hatch 21.0 m below the surface. calculate the force (in n) needed to

Tanzania [10]

Answer:

28,400 N

Explanation:

Let's start by calculating the pressure that acts on the upper surface of the hatch. It is given by the sum of the atmospheric pressure and the pressure due to the columb of water, which is given by Stevin's law:

$p_{top} = p_{atm} + \rho g h=1.013\cdot 10^5 Pa + (1000 kg/m^3)(9.8 m/s^2)(21.0 m)=3.071 \cdot 10^5 Pa$

On the lower part of the hatch, there is a pressure equal to

$p_{bot}=p_{atm}=1.013\cdot 10^5 Pa$

So, the net pressure acting on the hatch is

$p=p_{top}-p_{bot}=3.071 \cdot 10^5 Pa - 1.013\cdot 10^5 Pa=2.058 \cdot 10^5 Pa$

which acts from above.

The area of the hatch is given by:

$A=\pi r^2 = \pi (\frac{0.420 m}{2})^2=0.138 m^2$

So, the force needed to open the hatch from the inside is equal to the pressure multiplied by the area of the hatch:

$F=pA=(2.058\cdot 10^5 Pa)(0.138 m^2)=28,400 N$

8 0

3 years ago

List the following types of electromagnetic radiation in order of increasing wavelength:(i) the gamma rays produced by a radioac

Naddik [55]

Answer:

In order of increasing wavelength, the answer is:

(i) The gamma rays produced by a radioactive nuclide used in medical imaging

(iv) The yellow light from sodium-vapor streetlights

(v) The red light of a light emitting diode, such as in a calculator display

(ii) Radiation from an FM radio station at 93.1 MHz on the dial

(iii) A radio signal from an AM radio station at 680kHz on the dial

Explanation:

First, you have to know that the wavelength of a sinusoidal wave traveling at a constant speed is given by:

λ $= \frac{v}{f}$

Where λ is the wavelength, $v$ is the constant speed and $f$ is the wave's frequency. In the case of electromagnetic radiation in free space, the constant speed is the speed of light.

From explained above, you can conclude that there is a proportionality relationship between the wavelength and the frequency, they are inversely proportional. That means: the highest frequency will have the shortest wavelength and vice-versa.

So, you have the following types:

(i) The gamma rays produced by a radioactive nuclide used in medical imaging

Frequency : Typically greater than $10^{19}$ Hz

(ii) Radiation from an FM radio station at 93.1 MHz on the dial

Frequency: 93.1 MHz

(iii) A radio signal from an AM radio station at 680 kHz on the dial

Frequency: 680 kHz

(iv) The yellow light from sodium-vapor streetlights

Frequency: Visible spectrum of approx. 508 - 526 THz

(v) The red light of a light-emitting diode, such as in a calculator display

Frequency: Visible spectrum of approx. 400 - 484 THz

Then, you have to organize them from the highest frequency to the smallest one (decreasing frequency), and as the highest frequency will have the shortest wavelength, you are going to have it organized in an increasing wavelength mode.

Then in order of increasing wavelength, the answer will be:

(i) , (iv), (v), (ii), (iii)

3 0

4 years ago

Add me and ill add you back!! you have to bc i just gave you free coins :)

Rainbow [258]

Answer:

yoooooooooooooooooooo

Explanation:

6 0

3 years ago

Read 2 more answers

The total kinetic energy of two cars is measured before and after they crash into each other. The total kinetic energy of the tw

jenyasd209 [6]

Answer:

Option B, Some of the cars' kinetic energy was converted to sound and heat energy.

Explanation:

In an elastic collision, no energy is lost during and after collision. Thus, it can be said that in an elastic collision both momentum and kinetic energy remains conserved.

While in non-elastic collision, kinetic energy of the system is lost. However, the momentum of the system is conserved. Generally, during and after collision some of the kinetic energy is lost as thermal energy, sound energy etc.

Hence, option B is correct

4 0

3 years ago

A 4350 kg truck, driving 7.39 m/s, runs into the back of a stationary car. After the collision, the truck moves 4.55 m/s and the

DiKsa [7]

Answer:

Mass of car = 1098 kg

Explanation:

Here law of conservation of momentum is applied.

Let mass of car be m.

Initial momentum = Final momentum.

Initial momentum = 4350 x 7.39 + m x 0 = 32416.5 kgm/s

Final momentum = 4350 x 4.55 + m x 11.5 = 19792.5+11.5m

We have

19792.5+11.5m = 32416.5

m = 1097.97 kg

Mass of car = 1098 kg

4 0

3 years ago