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Nostrana [21]
2 years ago
9

A wooden disk of mass m and radius r has a string of negligible mass is wrapped around it. If the disk is allowed to fall and th

e string is held so that it unravels without sliding as the disk is falling, what will be the wooden disk's acceleration? What would be the tension on string in the process?
Physics
1 answer:
Tju [1.3M]2 years ago
7 0

Answer:

a = \frac{2}{3}g

T = \frac{mg}{3}

Explanation:

As the disc is unrolling from the thread then at any moment of the time

We have force equation as

mg - T = ma

also by torque equation we can say

TR = I\alpha

TR = \frac{1}{2}mR^2(\frac{a}{R})

T = \frac{1}{2}ma

Now we have

mg - \frac{1}{2}ma = ma

mg = \frac{3}{2}ma

a = \frac{2}{3}g

Also from above equation the tension force in the string is

T = \frac{1}{2}ma

T = \frac{mg}{3}

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: The truck is to be towed using two ropes. Determine the magnitudes of forces FA and FB acting on each rope in order to develop
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Answer:

Fa=774 N

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Explanation:

We will solve this problem by equating forces on each axis.

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  2. On y-axis let forces in positive y-direction be positive and forces in negative y-direction be negative

While towing we know that car is mot moving in y-direction so net force in y-axis must be zero

⇒∑Fy=0

⇒Fa*sin(50)-Fb*sin(20)=0

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⇒Fa=2.24Fb

Given that resultant force on car is 950N in positive x-direction

⇒∑Fx=950  

⇒Fa*cos(20)+Fb*cos(50)=950

⇒2.24*Fb*cos(20)+Fb(50)=950

⇒Fb*(2.24*cos(20)+cos(50))=950

⇒Fb=\frac{950}{2.24*cos(20)+cos(50)}

⇒Fb=\frac{950}{2.24*0.94+0.64}

⇒ Fb=\frac{950}{2.75}=345.5

⇒Fa=2.24*Fb

      =2.24*345.5

      =773.93

Therefore approximately, Fa=774 N and Fb=346 N

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2 years ago
Jim stands beside a wide river and wonders how wide it is. he spots a large rock on the bank directly across from him. he then w
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To solve this problem, we must imagine that Jim’s initial position, the position of the rock, and Jim’s final position all connects to form a triangle. Now we can imagine that the triangle is a right triangle with the 90° angle on the initial position.

The angle of 30° is directly opposite to the length of his total stride while the width of the river is the side adjacent to the angle. Therefore can use the tan function to solve for the width of the river:

tan θ = opposite side / adjacent side

tan 30 = total stride distance / width of river

where total stride distance = 65 * 0.8 = 52 m

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<span>width of river = 90.07 m</span>

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Which best describes the importance of mitosis to living organisms? genetic variation and growth growth and development developm
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a film of transparent material 120 nm thick and having refractive index 1.25 is placed on a glass sheet having refractive index
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Answer:

a) 600nm

b) 300nm

Explanation:

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n = refractive index of glass

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(b)

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L = 2tn

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= 300 nm

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2 years ago
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