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3 years ago

6

While a roofer is working on a roof that slants at 36.0 Â° above the horizontal, he accidentally nudges his 86 0 N toolbox, caus

ing it to start sliding downward, starting from rest If it starts 4.00 m from the lower edge of the roof, how fast will the toolbox be moving just as it reaches the edge of the roof if the kinetic friction force on it is 22.0 N?

1 answer:

Nataliya [291]3 years ago

7 0

Answer:

Explanation:

mass of the toolbox = 86 / 9.8

= 8.775 kg

Net force acting on the toolbox down the roof

= mgsin36 - kinetic friction

= 86 x .5877 - 22

= 28.54 N

acceleration of box = 28.54 / 8.775

a = 3.25 m /s²

v² = u² + 2 a s

u = 0 , a = 3.25 , s = 4 m

v² = 2 x 3.25 x 4

v = 5.1 m / s

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4 years ago

Read 2 more answers

how many days does it take a team of drivers to drive a truck california and back to lansing if the drivers average 15m/s includ

malfutka [58]

4days and 12hours

Explanation:

Given parameters:

Average speed = 15m/s

Distance = 1800 miles

Unknown:

Number of days = ?

Solution:

Speed is the rate of change of distance with time;

Speed = $\frac{distance}{time}$

Since the unknown is number of days, it is a measure of time:

Time = $\frac{distance }{speed}$

The distance from California to Lansing is 1800miles. The journey takes the truck drivers to and fro. It is a two way trip;

Total distance = 1800 miles x 2 = 3600miles

We need to convert miles to meters since that is the unit we can conveniently work with;

1 mile = 1609.34m

3600 miles = 3600 x 1609.34

= 5793638m

Inputting the values in the equation:

Time = $\frac{ 5793638}{15}$ = 386242.53s

Now we need to convert to day;

In a day, = 60 x 60 x 24 = 86,400s

1 day = 86400s

Therefore;

The number of days = $\frac{386242.53}{86400}$ = 4.47days

This implies that it will take them 4 days and approximately 12 hours.

learn more:

speed brainly.com/question/10048445

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3 years ago

An electron is confined in a harmonic oscillator potential well. What is the longest wavelength of light that the electron can a

kipiarov [429]

Answer:

The longest wavelength of light is 209 nm.

Explanation:

Given that,

Spring constant = 74 N/m

Mass of electron $m= 9.11\times10^{-31}\ kg$

Speed of light $c= 3\times10^{8}\ m/s$

We need to calculate the frequency

Using formula of frequency

$f =\dfrac{1}{2\pi}\sqrt{\dfrac{k}{m}}$

Where, k= spring constant

m = mass of the particle

Put the value into the formula

$f=\dfrac{1}{2\pi}\sqrt{\dfrac{74}{9.11\times10^{-31}}}$

$f=1.434\times10^{15}\ Hz$

We need to calculate the longest wavelength that the electron can absorb

$\lambda=\dfrac{c}{f}$

Where, c = speed of light

f = frequency

Put the value into the formula

$\lambda =\dfrac{3\times10^{8}}{1.434\times10^{15}}$

$\lambda=2.092\times10^{-7}\ m$

$\lambda=209\ nm$

Hence, The longest wavelength of light is 209 nm.

6 0

3 years ago

Heat is extracted from a certain quantity of steam at

vodomira [7]

Answer: $v=2452.91 m/s$

Explanation:

Given

initially steam is at $100^{\circ}C$ and converted to $0^{\circ} C$ ice

Let m be the mass of steam

latent heat of fusion and vaporization for water is

$L_f=3.33\times 10^5 J/kg$

$L_v=2.26\times 10^6 J/kg$

Heat required to convert steam in to water at $100^{\circ}C$

$Q_1=m\times L_v=m\cdot 2.26\times 10^6 J$

Heat required to lower water temperature to $0^{\circ}C$

$Q_2=m\times c\times \Delta T$

$Q_2=m\times 4.184\times (100)$

$Q_2=4.184m\times 10^5 J$

Heat required to convert $0^{\circ}C$ water to ice at $0^{\circ}C$ is

$Q_3=m\times L_f$

$Q_3=m\times 3.33\times 10^5=3.33m\times 10^5 J$

$Q=Q_1+Q_2+Q_3$

$Q=(2.26+0.4184+0.33)m\times 10^6 J$

$Q=3.0084m\times 10^6 J$

So this energy is equal to kinetic energy of bullet of mass m moving with velocity v

$Q=\frac{1}{2}mv^2$

$3.0084m\times 10^6=\frac{1}{2}mv^2$

$v^2=3.0084\times 2\times 10^6$

$v=2.452\times 10^3 m/s$

$v=2452.91 m/s$

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4 years ago

Calculate the height of stairs a 60 kg student would have to run in order to burn off 1 Calorie of food energy, which is the equ

Trava [24]

The height of stairs a 60 kg student would have to run in order to burn off 1 Calorie of food energy will be 7.1 meters.

<h3>What is potential energy?</h3>

The potential energy is due to the virtue of the position and the height. The unit for the potential energy is the joule.

Given data;

Mass of student,m = 60 kg

Energy,E = 4190 J

Height of stairs,h=?

The potential energy is mainly dependent upon the height of the object. The potential energy is found as;

Potential energy = mgh

E=mgh

h=E/mg

h= 4190 J / (60 kg× 9.81 m/s²)

h = 7.1 metre

Hence the height of the stairs will be 7.1 meters.

To learn more about the potential energy, refer to the link;

brainly.com/question/24284560

#SPJ1

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2 years ago