Question

A hollow cylinder of mass M and radius R rolls down an inclined plane. a block of mass M slides down an identical inclined plane. if both objects are released at the same time,
a) the cylinder will reach bottom first
b)the block will reach the bottom first
c) the block will reach the bottom with greater kinetic energy
d) the cylinder will reach bottom with greater kinetic energy
e) the block and the cylinder will reach the bottom at the same time.

Answer 1

i think it would be e

Answer 2

can you explain it conceptually please :] because i got e also but I'm not sure if my equation is right and not sure if its a?

Answer 3

the block reaches first, here is the explaination

Answer 4

the acceleration of the block is gsin@ where @ is the angle of inclination,

but for the cylinder after applying a couple of equations the acceleration comes out to be 2/3gsin@

Answer 5

so the answer should be b, is it?

Answer 6

i thought so at first but then theres no friction and gravity is constant

Answer 7

if u drop a pen and pencil at the same time they will hit th e floor at the same time

Answer 8

@mandapanda whers my medal,
;)

Answer 9

very true blueheart but its not the same when one of the object is rolling

Answer 10

I LOVE YOU <3 stom

Answer 11

this is true :)

Answer 12

OMG ,
erm
ur joking right

Answer 13

Btw ur questions are very sweet, involving rotational dynamics,

so do u want me to explain the working also ,
or u got it,
@mandapanda

Answer 14

well I'm in physics B ap thats how far we are right now. your explanation was really helpful !

Answer 15

do u mind if i ask whats physics b

Answer 16

its physics AP . there is physics regular , physics B Ap (no calculus) and Physics C AP (which involves calculus).

Answer 17

ok so thats how they have in the us,
hmm,
so u dont have to deal with calculus in physics as of yet,
,
so this question came in ur school exam,

shall i give u a question , which according to me is a really tough question in calculus?

Answer 18

sure

Answer 19

where are you from?

Answer 20

am from india,
(ever heard of it before)
:)

Answer 21

yes

Answer 22

so the question says,
a disc is set rotating about its axis,
and is kept HORIZONTALLY (with its axis of rotation perpendicular to the surface)
on a rough surface with k as the coefficient of friction,
and we r asked to calculate the time after which the disc stops rotating

Answer 23

my guess is you use conservation of energy to find the velocity and then find time using the velocity you found

Answer 24

since there is friction, energy cannot be conserved,
:)
(do i sound evil)