wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

A block of mass m is attached to a pulley disc of equal mass m and radius r by means of a slack string as shown. The pulley is hinged about its centre on a horizontal table and the block is projected with an initial velocity of 5m/s. Its velocity when the string becomes taut will be
120427_da4752ebc2c24038a61315fd1713baf3.png

A
3 m/s
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
2.5 m/s
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
53 m/s
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
103 m/s
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution

The correct option is C 103 m/s
We have momentum variation for final and initial velocities of the block as
P=m(v2v1)
Similarly for pulley
L=I(ω2ω1)=Iω2 (as initial velocity of pulley is zero)
equating the moment of the linear momentum of the block to the angular momentum of the pulley we get
m(v2v1)r=Iω2(here the minus sign shows the force on the pulley is opposing to the force on the block)
or
m(v1v2)r=mr22×v2r
or
2(v1v2)=v2
or
v2=23v1
or
v2=23(5)=103m/s

flag
Suggest Corrections
thumbs-up
0
similar_icon
Similar questions
View More
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
How Do Rockets Fly in Space?
PHYSICS
Watch in App
Join BYJU'S Learning Program
CrossIcon