SATHEE: Kinematics Question 557

Kinematics Question 557

Question: When a ceiling fan is switched off it’s angular velocity reduces to 50% while it makes 36 rotations.How many more rotation will it make before coming to rest (Assume uniform angular retardation)[KCET 2001]

Options:

A) 18

B)12

C) 36

D) 48

Show Answer

Answer:

Correct Answer: B

Solution:

By using equation $ω^{2} = ω_{0}^{2} - 2 α θ$

${(\frac{ω_{0}}{2})}^{2} = ω_{0}^{2} - 2 α (2 π n)$

therefore $α = \frac{3}{4} \frac{ω_{0}^{2}}{4 π \times 36}$ , (n = 36) ..(i)

Now let fan completes total n¢ revolution from the starting to come to rest $0 = ω_{0}^{2} - 2 α (2 π n^{'})$

therefore $n^{'} = \frac{ω_{0}^{2}}{4 α π}$

substituting the value of a from equation (i) $n^{'} = \frac{ω_{0}^{2}}{4 π} \frac{4 \times 4 π \times 36}{3 ω_{0}^{2}} = 48$

revolution Number of rotation = 48 - 36 = 12

Kinematics Question 557

Question: When a ceiling fan is switched off it’s angular velocity reduces to 50% while it makes 36 rotations.How many more rotation will it make before coming to rest (Assume uniform angular retardation)[KCET 2001]

Options:

Answer:

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

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Sample Mock Test

Mentorship

NCERT Exercise Video Solution

Kinematics Question 557

Question: When a ceiling fan is switched off it’s angular velocity reduces to 50% while it makes 36 rotations.How many more rotation will it make before coming to rest (Assume uniform angular retardation)[KCET 2001]

Options:

Answer:

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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