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2 years ago

A 105 kg crate initially at rest on a horizontal floor requires a 705 N horizontal force

Physics

1 answer:

DENIUS [597]2 years ago

3 0

Answer:

μs = 0.68

μk = 0.577

Explanation:

In order to solve this problem, we must remember that the normal force on a body that rests on a horizontal surface is equal to the weight of a body but in the opposite direction.

$W=N\\N=m*g\\N=105*9.81\\N=1030.05[N]$

The friction force is defined as the product of the coefficient of friction by the normal force.

Now when the body is in motion we have that the coefficient of friction is the dynamic one.

595 = μk*N

μk = 595/1030.05

μk = 0.577

Now to start moving it requires a force of 705 [N].

705 = μs*N

μs = 705/1030.05

μs = 0.68

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When the acceleration of a mass on a spring is zero, the velocity is at a

Sergeu [11.5K]

1) Maximum

2) Maximum

Explanation:

The force acting on a mass on a spring is given by Hooke's law; in magnitude:

$F=kx$

where

F is the force

k is the spring constant

x is the displacement

Also we know from Newton's second law that we can write

$F=ma$

where

m is the mass

a is the acceleration

So we can write the equation as

$ma=kx$ (1)

From this relationship, we see that the acceleration is directly proportional to the displacement.

On the other hand, we know that the total mechanical energy of the system mass-spring is constant, and it is given by

$E=\frac{1}{2}kx^2+\frac{1}{2}mv^2=const.$ (2)

where the first term is the elastic potential energy while the second term is the kinetic energy, and where

v is the velocity of the mass

From eq. (2), it is clear that when displacement increases, velocity decreases, and vice-versa; however, from eq.(1) we also know that acceleration is proportional to the displacement.

Therefore this means that:

- When acceleration increases, velocity decreases

- When acceleration decreases, velocity increases

Therefore, the two answers here are:

- When the acceleration of a mass on a spring is zero, the velocity is at a maximum

When the velocity of a mass on a spring is zero, the acceleration is at a maximum

6 0

2 years ago

1. why did aristarchus choose the time of a half (quarter) moon to make his measurements for calculating the earth-sun distance?

Stells [14]

In order to make his measurements for determining the Earth-Sun distance, Aristarchus waited for the Moon's phase to be exactly half full while the Sun was still visible in the sky. For this reason, he chose the time of a half (quarter) moon.

<h3 /><h3>How did Aristarchus calculate the distance to the Sun?</h3>

It was now possible for another Greek astronomer, Aristarchus, to attempt to determine the Earth's distance from the Sun after learning the distance to the Moon. Aristarchus discovered that the Moon, the Earth, and the Sun formed a right triangle when they were all equally illuminated. Now that he was aware of the distance between the Earth and the Moon, all he needed to know to calculate the Sun's distance was the current angle between the Moon and the Sun. It was a wonderful argument that was weakened by scant evidence. Aristarchus calculated this angle to be 87 degrees using only his eyes, which was not far off from the actual number of 89.83 degrees. But when there are significant distances involved, even slight inaccuracies might suddenly become significant. His outcome was more than a thousand times off.

To know more about how Aristarchus calculate the distance to the Sun, visit:

brainly.com/question/26241069

#SPJ4

7 0

1 year ago

An organ pipe is made to play a low note at 27.5 Hz, the same as the lowest note on a piano. Assuming a sound speed of 343 m/s,

timama [110]

Answer:

The length of open-open pipe needed is 6.23 m

The length of open-close pipe needed is 3.11 m

Explanation:

Fundamental frequency for standing wave mode of an open- open pipe is given by

$f=\frac{v}{2L}$

where v is the velocity and L is the length

The length of open-open pipe needed is

$L=\frac{v}{2f} \\L=\frac{343}{2\times 27.5} \\L=6.23 m$

Fundamental frequency for standing wave mode of an open- close pipe is given by

$f=\frac{v}{2L}$

The length of open-close pipe needed is

$L=\frac{v}{2f} \\L=\frac{343}{2\times 27.5} \\L=6.23 m$

7 0

3 years ago

A young girl is on a swing that completes 35.0 cycles in 25 seconds. What are her frequency and period?

fgiga [73]

The first question has the answer to your problem! I found the answer key!

3 0

2 years ago

An unknown mass of each substance, initially at 25.0 ∘C, absorbs 1920 J of heat. The final temperature is recorded. Find the mas

zhannawk [14.2K]

Answer: mass for Pyrex glass 84.21g

mass for sand 61.6g

mass for ethanol 41.32g

mass for water 62.07g

Explanation

By definition specific heat is the amount of heat required to change the temperature of 1 kg mas by 1°C

Q=mcΔT is formula for specific heat

Q is heat transfer

m is mass

ΔT is change in temperature

c is specific heat

c of Pyrex glass= 0.75 j/g°C

c of sand = 0.84 j/g°C

c of ethanol= 2.42 j/g°C

c of water = 4.18 j/g°C

now we will make M(mass) the subject, so equation becomes

m=Q/cΔT

for

pyrex glass T<em>f=</em>55.4°C

m=1920/(55.4-25)*0.75

m=84.21g {after cutting J(joules) and °C we are left with g(grams)}

for

sand T<em>f</em>=62.1°C

m=1920/(62.1-25)*0.84

m=61.6g {after cutting J(joules) and °C we are left with g(grams)}

for

ethanol T<em>f</em>=44.2°C

m=1920/(44.2-25)*2.42

m=41.32g {after cutting J(joules) and °C we are left with g(grams)}

for

water T<em>f=</em>32.4°

m=1920/(32.4-25)*4.18

m=62.07g {after cutting J(joules) and °C we are left with g(grams)}

i hope you understand the solution, thank you.

7 0

2 years ago