PHYSICS COLLEGE

As a science project, you drop a watermelon off the top of the Empire State Building. 320 m above the sidewalk. It so happens that Superman flies by at the instant you release the watermelon. Superman is headed straight down with a constant speed of 30 m/s. A) How much time passes before the watermelon has the same velocity? B) How fast is the watermelon going when it passes Superman?C) How fast is the watermelon traveling when it hits the ground?

Answers

Answer 1

Answer:

Answer:

3.06 seconds time passes before the watermelon has the same velocity

watermelon going at speed 59.9 m/s

watermelon traveling when it hits the ground at speed is 79.19 m/s

Explanation:

given data

height = 320 m

speed = 30 m/s

to find out

How much time passes before the watermelon has the same velocity and How fast is the watermelon going and How fast is the watermelon traveling

solution

we will use here equation of motion that is

v = u + at ....................1

here v is velocity 30 m/s and u is initial speed i.e zero and a is acceleration i.e 9.8 m/s²

put the value and find time t

30 = 0 + 9.8 (t)

t = 3.06 s

so 3.06 seconds time passes before the watermelon has the same velocity

and

we know superman cover distance is = velocity × time

so distance = 30 × t

and distance formula for watermelon is

distance = ut + 0.5×a×t² .............2

here u is initial speed i.e 0 and a is acceleration i.e 9.8 m/s² and h is 30 × t

30 × t = 0 + 0.5×9.8×t²

t = 6.12 s

so by equation 1

v = u + at

v = 0 + 9.8 ( 6.12)

v = 59.9 m/s

so watermelon going at speed 59.9 m/s

and

watermelon traveling speed formula is by equation of motion

v² - u² = 2as ......................3

here v is speed and u is initial speed i.e 0 and a is acceleration i.e 9.8 m/s² and s is distance i.e 320 m

v² - 0 = 2(9.8) 320

v = 79.19 m/s

so watermelon traveling when it hits the ground at speed is 79.19 m/s

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Answers

The average wavelength of radio waves ranges from roughly two millimeters to more than 150 kilometers. The wavelengths of radio waves are the longest in the electromagnetic spectrum

What is Wavelength?

It can be understood in terms of the distance between any two similar successive points across any wave for example wavelength can be calculated by measuring the distance between any two successive crests.

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C = νλ

They also have the lowest frequencies, ranging from around 4,000 cycles per second, or 3 kilohertz, to roughly 280 billion hertz, or 280 gigahertz.

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To learn more about wavelength from here, refer to the link given below;

brainly.com/question/7143261

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Answer:

Radio waves have frequencies as high as 300 gigahertz(GHz)to as low as 30 hertz(Hz).At 300 GHz the corresponding wavelength is 1mm and at 30Hz is 10,000 km

A proton and an alpha particle (helium nucleus consisting of two protons and two neutrons) are accelerated from rest across the same potential difference. Assume the proton mass and the neutron mass are roughly the same and neglect any relativistic effect. Compared to the final speed of the proton, the final speed of the alpha particle is?1. less by a factor of 22. less by a factor of √ 23. less by a factor of 44. greater by a factor of 25. the same

Answers

Answer:

option B

Explanation:

we know,

change in energy is equal to

$W = (1)/(2)m(v^2 - u^2)$

$W = (1)/(2)m(v^2 - 0^2)$

$W = (1)/(2)m v^2$

$q = (1)/(2)m v^2$

proton mass and the neutron mass are roughly the same

so,

$q \alpha m v^2$

now,

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$(q_p)/(q_(\alpha)) = (m_p v_p^2)/(2 m_pv_(\alpha)^2)$

we know,

mass of alpha particle is four times mass of the mass of proton.

mα = 4 m_p

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$( v_p^2)/(v_(\alpha)^2) = 2$

$v_(\alpha)^2 =( v_p^2)/(2)$

$v_(\alpha)=( v_p)/(√(2))$

less by a factor of √2

Hence, the correct answer is option B

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Answers

Two parallel coils separated by a distance equal to the radius of the coils are known as Helmholtz coils. They are frequently used because they generate a magnetic field that is uniform over an appreciable region about its midpoint.

Consider a situation where a constant force of 25 N acts on an object having a mass of 2 kg for 3 seconds. What is the work done by the force

Answers

Answer:

Work done W =1406.25 J

Explanation:

Work done on a body can be calculated using newton's 2nd laws:

F=ma

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Hence acceleration of the block is given by:

$\Rightarrow a=(25)/(2)=12.5m/s^2$

Displacement of the object is given by:

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Substitute the values

$\Rightarrow S=0*3+(1)/(2)(12.5)3^2$

$\Rightarrow S=56.25 m$

Now work done is given by:

W=F.S

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A racing car is travelling at 70 m/s and accelerates at -14 m/s2. What would the car’s speed be after 3 s?

Answers

Question:

A racing car is travelling at 70 m/s and accelerates at -14 m/s^2. What would the car’s speed be after 3 s?

Statement:

A racing car is travelling at 70 m/s and accelerates at -14 m/s^2.

Solution:

Initial velocity (u) = 70 m/s
Acceleration (a) = -14 m/s^2
Time (t) = 3 s
Let the velocity of the car after 3 s be v m/s
By using the formula,

v = u + at, we have

$v = 70 + ( - 14)(3) \n = > v = 70 - 42 \n = > v = 28$

So, the velocity of the car after 3 s is 28 m/s.

Answer:

The car's speed after 3 s is 28 m/s.

Hope it helps

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