1

A small block with mass m is attached to a cord passing through a hole in...

Question

A small block with mass m is attached to a cord passing through a hole in...

A small block with mass m is attached to a cord passing through a hole in a frictionless, horizontal surface. The block is initially revolving at a distance r from the hole with a speed vr. as shown. (a) By what force F, applied by the hand is the block held rotating? The cord is then pulled additionally from below, shortening the radius of the circle in which the block revolves to At this new distance, (b) what will the final speed v2 of the block be? (c) By what force F2 will the block be held rotating now? (d) How much was the total work IV, done on m? (e) How much was the work Wr done by the person who pulled on the cord?

4. A small block with mass m is attached to a cord passing through a hole in a frictionless, horizontal surface. The block is

4. A small block with mass m is attached to a cord passing through a hole in a frictionless, horizontal surface. The block is initially revolving at a distance r from the hole with a speed vi, as shown. (a) By what force F, applied by the hand is the block held rotating? The cord is then pulled additionally from below, shortening the radius of the circle in which the block revolves to r/2. At this new distance, (b) what will the final speed v2 of the block be? (c) By what force F2 will the block be held rotating now? (d) How much was the total work W. done on m? (e) How much was the work W: done by the person who pulled on the cord?

Answers


Given
mass of the block m , moving on a frictionless horizontal surface, in circular path
initially with velocity v1 and radius r1,
a) In order to held the block rotating there should be a force towards the center called centripetal force is given by

   F1 = m*v1^2/r1
b) if the block is pulled down by the cord then

By conservation of angular momentum

   L1 = L2

   m*v1*r1 = m*v2*r2

   v1*r1 = v2*r2
r2 = r1/2
   v1*r1 = v2*r1/2

   v2 = 2*v1

c) the force required is

   F2 = m*v2^2/r2

   F2 = m*4*v1^2/(r1/2)
   F2 = 8 m*v1^2/r1

   F2 = 8*F1
d) Total work done on m is W

By work energy theorem

   W = change in kinetic energy

   W = 0.5*m(v2^2-v1^2)

  


Similar Solved Questions

1 answers
How do you simplify #4/a-1/(3a)#?
How do you simplify #4/a-1/(3a)#?...
1 answers
What is the radical expression of #4d ^(3/8)#?
What is the radical expression of #4d ^(3/8)#?...
1 answers
Which of the following is true regarding activity based costing ? A. The benefits of using...
Which of the following is true regarding activity based costing ? A. The benefits of using ABC always outweigh its limitations B. The lower the proportion of overhead costs as compared to direct materials and direct labor costs, the more likely a company will benefit from using ABC C. Companies with...
1 answers
Oral Health Objective Reduce the proportion of children and adolescents who have dental caries experience in...
Oral Health Objective Reduce the proportion of children and adolescents who have dental caries experience in their primary or permanent teeth 1) you think this oral health objective will be meet by 2020? Explain your response 2)Provides examples of what a heath education specialist can do to help me...
1 answers
Gold Mining, Inc. is using the profitability index (PI) when evaluating projects. Gold Mining’s cost of...
Gold Mining, Inc. is using the profitability index (PI) when evaluating projects. Gold Mining’s cost of capital is 11.35 percent. What is the PI of a project if the initial costs are $2,118,606 and the project life is estimated as 5 years? The project will produce the same after-tax cash inflo...
1 answers
Question 4 20 pts A company approaches a bank and wants to deposit $7m from the...
Question 4 20 pts A company approaches a bank and wants to deposit $7m from the bank starting in 175 days for 90 days. The bank sees the current market information as • 175 day continuously compounded rate is 3.8671%. • There is a Eurodollar futures contract expiring in 175 days with a pri...
1 answers
1. Questions (a) Truncations chooses the closest machine number in the direction towards zero. This implies...
1. Questions (a) Truncations chooses the closest machine number in the direction towards zero. This implies that for positive numbers the result is less or equal than the original mumber while for negative numbers the result of truncation is larger or equal than the original number. Round to nearest...
1 answers
3. Ambien is a prescription sedative. do oso do ano 2. - รู้ Zolpidem (Ambien) OH...
3. Ambien is a prescription sedative. do oso do ano 2. - รู้ Zolpidem (Ambien) OH D a. The most electrophilic atom in Ambien is Be specific Your answer b. The structures of the metabolic (hydrolysis under acid conditions) products of this compound is/are a. The most electrophilic a...
1 answers
Given the following circuit, calculate Vi, V2, V3, Ir, I, h, , 14 using nodal analysis....
Given the following circuit, calculate Vi, V2, V3, Ir, I, h, , 14 using nodal analysis. l54 www 100k 1k 10k 1k V2 V1 IT 10k 100k 1k 5V 12...
1 answers
5) When materials are requisitioned for use in production in a job order costing firm, the...
5) When materials are requisitioned for use in production in a job order costing firm, the cost of materials is added to the a) Raw materials account b) Work-in-process account c) Finished goods account d) Accounts payable account e) Cost of goods sold account...
1 answers
Classify the three active accounting E1.1 (LO 1) Genesis Company performs the following accounting tasks during...
Classify the three active accounting E1.1 (LO 1) Genesis Company performs the following accounting tasks during the year. Analyzing and interpreting information. Classifying economic events. Explaining uses, meaning, and limitations of data. Keeping a systematic chronological diary of events. Measur...
1 answers
Annual demand for educational toys in the city of Lambert is 1,200 units. The fixed ordering...
Annual demand for educational toys in the city of Lambert is 1,200 units. The fixed ordering cost is $41, and the holding cost is known to be always $2 per unit per year regardless of unit price. The contract offered by the supplier is an all-units discount and consists of the following price schedu...
1 answers
1-12 Judge the following statements as true (T) or false (F) A. Air and water are...
1-12 Judge the following statements as true (T) or false (F) A. Air and water are both elements. B. All mixtures contain at least one element and one compound. C. Elements can exist in any of the 3 states of matter. D. When yellow stains in the kitchen sink are treated with E. The number 0.0033 has ...
1 answers
Question 6 The denominator of the rate of return on total assets ratio is the average...
Question 6 The denominator of the rate of return on total assets ratio is the average total assets. a. False b. True...
1 answers
How would you synthesize the following compound from acetylene and reagents in the table? Choose the...
How would you synthesize the following compound from acetylene and reagents in the table? Choose the most efficient route. Specify reagents using letters from the table, first reagent on the left. Example: ab H H CH3CH2CH2 CH2CH3 a. Br2 b. CH3CH I Reagents available d. CH3 CH2CH2CH2Br g. KOH/ ethano...
1 answers
I compounds are aspirin (acetyl salicylic acid) and methyl salicylate (i.e. alcohols, aldehydes, ketones, acids, esters,...
I compounds are aspirin (acetyl salicylic acid) and methyl salicylate (i.e. alcohols, aldehydes, ketones, acids, esters, amides, etc)? 5. Describe what physiological effects aspirin causes in the body, eg. regarding body temperature, pain, swelling and thrombosis (blood clotting). Does it inhibit an...
1 answers
Compute the DTFTs for the following signals. In a. x[n] = (3)" u[-n – 1] b....
Compute the DTFTs for the following signals. In a. x[n] = (3)" u[-n – 1] b. x[n] = 2” sin (n)u[-n]...
1 answers
Return to question 8 rporation, a manufacturer of steel products, began operations on October 1, 2019....
Return to question 8 rporation, a manufacturer of steel products, began operations on October 1, 2019. The accounting department of ted the fixed-asset and depreciation schedule presented below. You have been asked to assist in completing this on to ascertaining that the data already on the schedule...
1 answers
An object moves along the x axis according to the equation x 3.102 2.00t 3.00, where...
An object moves along the x axis according to the equation x 3.102 2.00t 3.00, where x is in meters and t is in seconds. (a) Determine the average speed between t 2.40 s and t-4.20 s. The average speed is the distance traveled divided by the time. Is the distance traveled equal to the displacement i...

-- 0.009797--