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3 years ago

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A car was moving at 14 m/s After 30 s, its speed increased to 20 m/s. What was the acceleration during this time ( need help fas

t!!!)

1 answer:

Arada [10]3 years ago

7 0

Answer:let initial velocity u=14m/s

Final velocity v=20m/s

Time taken t=30

Acceleration =a

V=u +at

a= (20-14)/30

a=0.2m/s^2

Explanation:

Acceleration is the change in velocity with respect to time.

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A Carnot engine operates between reservoirs at 600 and 300 K. If the engine absorbs 100 J per cycle at the hot reservoir, what i

PIT_PIT [208]

Answer:

W =50 J

Explanation:

given data:

T_h=600 k

T_L=300 k

Q_h=100 J

required:

<em>W=??</em>

<u>solution:</u>

║W║=║Q_h║(1-T_L/T_h)

=50 J

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3 years ago

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A graph of acceleration against force

enot [183]

The equation of the graph is

Force = (mass) x (acceleration) .

The graph is a straight line that passes through the origin,
and its slope is the mass of the object being studied.

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3 years ago

What are the average velocity and average acceleration of the tip of a 2.4 cm long hour hand of a clock?

ra1l [238]

A circle has a revolution of 360°. Since there are 12 hour markings, each hour interval has an angle of 30°. In radians, that would be equal to π/6 radians. So, in every 1 hour that passes, it covers π/6 of an angle. So, the angular velocity denoted as ω is π/6 ÷ 1 hour = π/6 rad/h. We can compute the average linear velocity, v, from the relationship:

v = rω, where r is the radius of the circle which is the length of the hour hand
v = (2.4 cm)(π/6 rad/h)
v = 1.257 cm/hour

Therefore, the average velocity is 1.257 cm per hour.

For the average acceleration, it is equal to zero. The hands of the clock move at a constant velocity. Since acceleration is the change of velocity per unit time, there is no change of velocity because it's constant. That's why it is zero.

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3 years ago

What can you infer about a wave with a short wavelength?

raketka [301]

Answer:

- It can be infer that it has a lower frequency.

<em>In the case of electromagnetic waves.</em>

- A short wavelength means a lower energy,

Explanation:

The wavelength is the distance between two consecutive crests or valleys while the frequency is the number of crests that pass for a specific point in an interval of time.

For example, a person makes laundry once a weak.

In this example, the event is represented by the laundry and the interval of time is once a weak

The velocity of a wave is defined as:

$v = \nu \cdot \lambda$ (1)

Where $nu$ is the frequency and $\lambda$ is the wavelenth

$\lambda = \frac{v}{\nu}$ (2)

Notice from equation 2 that the wavelength is inversely proportional to the frequency (when the wavelength increases the frequency decreases).

In the case of electromagnetic waves, a short wavelength means a lower energy, as it can be seen in equation 4 (inversely proportional).

$E = h\nu$ (3)

$E = \frac{hc}{\lambda}$ (4)

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3 years ago

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Concept Simulation 20.4 provides background for this problem and gives you the opportunity to verify your answer graphically. Ho

77julia77 [94]

Answer:

The time constant is 1.049.

Explanation:

Given that,

Charge $q{t}= 0.65 q_{0}$

We need to calculate the time constant

Using expression for charging in a RC circuit

$q(t)=q_{0}[1-e^{-(\dfrac{t}{RC})}]$

Where, $\dfrac{t}{RC}$ = time constant

Put the value into the formula

$0.65q_{0}=q_{0}[1-e^{-(\dfrac{t}{RC})}]$

$1-e^{-(\dfrac{t}{RC})}=0.65$

$e^{-(\dfrac{t}{RC})}=0.35$

$-\dfrac{t}{RC}=ln (0.35)$

$-\dfrac{t}{RC}=-1.049$

$\dfrac{t}{RC}=1.049$

Hence, The time constant is 1.049.

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3 years ago