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4 years ago

a man crossed a road 8.25m wide at a speed of 2.01m/s,how long does it take to get man to cross the road

Physics

1 answer:

Svetradugi [14.3K]4 years ago

5 0

Answer:

t = 4.1 seconds

Explanation:

It is given that,

Width of road which is to be crossed by a man is 8.25 m, it means it is distance to be covered.

Speed of man is 2.01 m/s

We need to find the time taken by the man to cross the road. It is a concept of speed. Speed of a person is given by total distance covered divided by time taken. So,

$v=\dfrac{d}{t}$

t is time taken

$t=\dfrac{d}{v}\\\\t=\dfrac{8.25}{2.01}\\\\t=4.1\ s$

So, the time taken by the man to cross the road is 4.1 seconds.

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3 years ago

Because the __ signal changes smoothly, like a sine wave, it can closely mimic a human voice. However, part of the signal can ea

Naya [18.7K]

Answer:

Analog,Noise,Digital,less

Explanation:

Analog signal changes continuously with time and moves smoothly.

Due to this analog signal can easily disturbed by noise.

Since digital signal are like square wave due to this digital signals are less affected by noise.

Because the Analog signal changes smoothly, like a sine wave, it can closely mimic a human voice. However, part of the signal can easily get lost to Noise. Because Digital signals are on or off, like a square wave, they best carry information that can easily be converted into numbers. These signals are less affected by noise.

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3 years ago

Mary applies a force of 73 N to push a box with an acceleration of 0.48 m/s^2. When she increases the pushing force to 84 N, the

nikklg [1K]

Answer: $68.75\ kg, 0.06$

Explanation:

Mary applies a force of 73 N to create an acceleration of $0.48\ m/s^2$

When She increases force to 84 N, it creates an acceleration of $0.64\ m/s^2$

Friction opposes the motion of box

$\Rightarrow 73-f=m\times 0.48\quad \ldots(i)\\\Rightarrow 84-f=m\times 0.64\quad \ldots(ii)$

Subtract (i) from (ii)

$\Rightarrow 11=m(0.64-0.48)\\\Rightarrow m=68.75\ kg$

Therefore friction is

$\Rightarrow f=73-68.75\times 0.48\\\Rightarrow f=73-33\\\Rightarrow f=40\ N$

Here, friction is kinetic friction which is given by

$\Rightarrow f=\mu_kmg\\\Rightarrow 40=\mu_k 68.75\times 9.8\\\Rightarrow \mu_k=0.061$

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3 years ago

Consider a 10 gram sample of a liquid with specific heat 2 J/gK. By the addition of 400 J, the liquid increases its temperature

stich3 [128]

40 J/g is the heat of vaporization of the liquid.

Answer: Option D

<u>Explanation:</u>

Given that mass of liquid sample: m = 10 g

And, Specific heat of the liquid: S = 2 J/g K

Also, the increase in the temperature of the liquid, $\Delta T = T_{2}-T_{1} = 10 K$

Therefore, the total amount of heat energy required is given by:

$q_{1} = m \times S \times\left(T_{2}-T_{1}\right) = 10 \times 2 \times 10 = 200 J$

According to the given data in the question,

Total heat energy supplied, q = 400 J

Rest of heat would be $q_{2}=q-q_{1}=400-200=200 \mathrm{J}$

Now, 200 J vaporizes the mass, half of the liquid from full portion boiled away. So,

$m^{\prime} = \frac{10}{2} = 5 \mathrm{g}$

Latent heat of vaporization of the liquid is $L_{v}$ . It can be calculated as below,

$q_{2} = m^{\prime} L_{v}$

$L_{v} = \frac{q_{2}}{m^{\prime}} = \frac{200}{5} = 40 \mathrm{J} / \mathrm{g}$

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3 years ago

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antiseptic1488 [7]

Answer:

1. In general, the best shields will be able to block a spectrum of radiation. Aboard the space station, the use of hydrogen-rich shielding such as polyethylene in the most frequently occupied locations, such as the sleeping quarters and the galley, has reduced the crew's exposure to space radiation.

2. It absorbs harmful ultraviolet radiation from the sun, helps keep Earth's surface warm via the greenhouse effect, and reduces temperature extremes between day and night. ... So, thanks to gravity, although some of Earth's atmosphere is escaping to space, most is staying here.

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3 years ago

a man crossed a road 8.25m wide at a speed of 2.01m/s,how long does it take to get man to cross the road​

a man crossed a road 8.25m wide at a speed of 2.01m/s,how long does it take to get man to cross the road