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3 years ago

A speed-time graph is shown below:

Physics

1 answer:

alexandr1967 [171]3 years ago

3 0

Answer:

The average acceleration of the object is 0.5 cm/s^2. Answer: A)

Explanation:

Average Acceleration

The average acceleration of a moving object is the rate at which the speed changed over time in a specific period. It can be calculated as follows:

$\displaystyle \bar a=\frac{v_f-v_o}{t}$

Where vf is the final speed, vo is the initial speed and t is the time.

The speed-time shows the speed starts at 0 cm/s and ends at 4 cm/s over the 8 seconds period. The average acceleration is:

$\displaystyle \bar a=\frac{4-0}{8}=0.5$

The average acceleration is 0.5 cm/s^2

A) Correct. The average acceleration is 0.5 cm/s^2

B) Incorrect. The average acceleration is 0.5 cm/s^2

C) Incorrect. The average acceleration is 0.5 cm/s^2

D) Incorrect. The average acceleration is 0.5 cm/s^2

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Describe a situation where you can be traveling at a low speed but have an extremely high velocity

Reil [10]

Answer:

Cruising at 35,000 feet in an airliner, straight toward the east,

at 500 miles per hour

Explanation:

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3 years ago

Read 2 more answers

How many photons are absorbed during the dental x-ray?

MariettaO [177]

E=hc/wav. len
E = (6.62 x 10^-34 x 3 x 10^8)/0.0275 x 10^-9
E = 7.22182 x 10^-15 J
To convert to eV divide by 1.6 x 10^-19
E = 7.22182 x 10^-15/1.6 x 10^-19 eV
E =45.36 x 10^3 eV
Th energy, E, of a single x-ray photon in eV is = 45.36keV.

Number of photons, n = total energy/ energy of photon
n = 3.85 x 10^-6/7.22182 x 10^-15
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3 years ago

Why do remote controls for TV’s use infrared waves to communicate?

Delvig [45]

Answer: An IR remote (also called a transmitter) uses light to carry signals from the remote to the device so it can be controlled. It emits pulses of invisible infrared light that correspond to specific binary codes. These codes represent commands, such as power on, volume up, or channel down.

Explanation:

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3 years ago

Three deer, a, b, and c, are grazing in a field. deer b is located 62.1 m from deer a at an angle of 54.3 ° north of west. deer

sveticcg [70]

by cosine law we know that

$c^2 = a^2 + b^2 - 2 abcos\theta$

$\theta = 180 - 54.3 - 79.1 = 46.6 degree$

now using above equation

$93.8^2 = 62.1^2 + b^2 - 2*62.1*b * cos46.6$

$4942.03 = b^2 - 85.34 b$

$b^2 - 85.34b - 4942.03 = 0$

by solving above quadratic equation we have

$b = 124.9 m$

so it is at distance 124.9 m from deer a

4 0

3 years ago

(A) how much work is done when you push a crate horizontally with 100 N across a 10-m factory floor?

Mila [183]

Answer:

A) 1000 joules

Explanation:

In general work is given by the equation:

$W=\intop_{a}^{b}\overrightarrow{F}\cdot d\overrightarrow{s}$ (1)

A) With $\overrightarrow{s}$ the displacement and $\overrightarrow{F}$ the force applied, because the force and the displacement are parallel (the crate is pushed horizontally) $\overrightarrow{F}\cdot d\overrightarrow{s}$ is simply $F\,ds$ , and because the path is a straight line and the force is constant work is:

$W=FS$ (2),

$W=(100)(10)=1000\,J$

B) The work-energy theorem says that the total work on a body is equal to the change on kinetic energy:

$W_{tot}=\varDelta K$ (3)

The total work on the crate is the work done by the push and plus the work of the friction $W_{tot}=W + W_{f}$ (4) , as (A) because forces are parallel to the displacement $W= FS$ (5) and $W_{f}=-fS$ (6), the due friction always has negative sign because is opposite to the displacement, using (6), (5) and (4) on (3):

$FS-fS=\varDelta K$ (3)

$1000-(70)(10)=300\,J$

C) The energy is lost by friction, so the amount of energy turned into heat is the work the friction does:

$Q=fS=(70)(100)=700\,J$ (3)

6 0

4 years ago