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Salsk061 [2.6K]
2 years ago
9

A train is traveling at a speed of 80\,\dfrac{\text{km}}{\text{h}}80 h km ​ 80, start fraction, start text, k, m, end text, divi

ded by, start text, h, end text, end fraction when the conductor applies the brakes. The train slows with a constant acceleration of magnitude 0.5\,\dfrac{\text{m}}{\text{s}^2}0.5 s 2 m ​ 0, point, 5, start fraction, start text, m, end text, divided by, start text, s, end text, squared, end fraction. We want to find the distance the train travels from the time the conductor applies the brakes until the train comes to a complete stop. Which kinematic formula would be most useful to solve for the target unknown? Choose 1 answer:
Physics
2 answers:
trasher [3.6K]2 years ago
7 0

Answer:

The distance the train travels before coming to a (complete) stop = 40/81 km which is approximately 493.83 meters

Explanation:

The initial speed of the train u = 80 km/h = 22 2/9 m/s = 22.\bar 2 m/s

The magnitude of the constant acceleration with which the train slows, a = 0.5 m/s²

Therefore, we have the following suitable kinematic equation of motion;

v² = u² - 2 × a × s

Where;

v = The final velocity = 0 (The train comes to a stop)

s = The distance the train travels before coming to a stop

Substituting the  values gives;

0² = 22.\bar 2² - 2 × 0.5 × s

2 × 0.5 × s = 22.\bar 2²

s = 22.\bar 2²/1 = 493 67/81 m = 40/81 km

The distance the train travels before coming to a (complete) stop = 40/81 km ≈ 493.83 m.

otez555 [7]2 years ago
4 0

Answer:

v^2=v0^2+2aΔx

Explanation:

cuz khan academy says so

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Describe the motion of a swing that requires 6 seconds to complete one cycle. What is its period and the frequency? Round to the
shutvik [7]

Period = 6 seconds and frequency = 0.167Hz .

<u>Explanation:</u>

We have , the motion of a swing that requires 6 seconds to complete one cycle. Period is the amount of time needed to complete one oscillation . And in question it's given that 6 seconds is needed to complete one cycle. Hence ,Period of the motion of a swing is 6 seconds . Frequency is the number of vibrations produced per second and is calculated with the formula of  \frac{1}{t} . SI unit of frequency is Hertz or Hz. We know that time period is 6 seconds so frequency =   \frac{1}{t}

⇒ frequency = \frac{1}{time}

⇒ frequency = \frac{1}{6}

⇒ frequency = 0.167Hz

Therefore , Period = 6 seconds and frequency = 0.167Hz .

7 0
3 years ago
g The potential energy of a pair of hydrogen atoms separated by a large distance x is given by U(x)=−C6/x6, where C6 is a positi
Arisa [49]

Answer:

F_x = -\frac{6 C_6}{2^7}

Attractive

Explanation:

Data provided in the question

The potential energy of a pair of hydrogen atoms given by \frac{C_6}{X_6}

Based on the given information, the force that one atom exerts on the other is

Potential energy μ = \frac{C_6}{X_6}

Force exerted by one atom upon another

F_x = \frac{\partial U}{\partial X} = \frac{\partial}{\partial X}  (-\frac{C_6}{X^6})

or

F_x = \frac{\partial}{\partial X}  (\frac{C_6}{X^6})

or

F_x = -\frac{6 C_6}{2^7}

As we can see that the C_6 comes in positive and constant which represents that the force is negative that means the force is attractive in nature

5 0
3 years ago
A discharge lamp rated at 25 W (1 W = 1 J/s) emits yellow light of wavelength 580 nm. How many photons of yellow light does the
Scrat [10]

Answer:

the number of photons of yellow light does the lamp generate in 1.0 s is 7 x 10^{19}

Explanation:

given information:

power, P = 25 W

wavelength. λ - 580 nm = 5.80 x 10^{-7} m

time, t = 1 s

to calculate the number of photon(N), we use the following equation

N = λPt/hc

where

λ = wavelength (m)

P = power (W)

t = time interval (s)

h = Planck's constant (6.23 x 10^{-34} Js)

c = light's velocity (3 x 10^{8} m/s^{2})

So,

N = λPt/hc

   = (5.80 x 10^{-7})(25)(1)/(6.23 x 10^{-34})(3 x 10^{8} m/s^{2})

    = 7 x 10^{19}

3 0
2 years ago
Two moles of an ideal monatomic gas are at a temperature of 345 K. Then, 2250 J of heat is added to the gas, and 870 J of work i
Lapatulllka [165]

Answer: The final temperature is 470K

Explanation: Using the relation;

Q= ΔU +W

Given, n = 2mol

Initial temperature T1= 345K

Heat =Q= 2250J

Workdone=W=-870J(work is done on gas)

T2 =Final temperature =?

ΔU =3/2nR(T2-T1)

ΔU=3/2 × 2 ×8.314 (T2 - 345)

ΔU=24.942(T2-345)

Therefore Q = 24.942(T2-345)+ (-870)

2250=24.942(T2-345)+ (-870)

125.09=(T2-345)

T2 =470K

Therfore the final temperature is 470K

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2 years ago
Which is a way that biotechnology has not helped society
nata0808 [166]
I would select answer C
6 0
2 years ago
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