Block and Hollow sphere move down a fricitonless inclined plane

[TuxDave]

Originally posted by: nourdmrolNMT1
The answer is C.

so says Purdue.

Which isn't correct given all the points stated above. It's a badly worded question. Now of the cylinder had a slope with no slippage, then the block would get there first.

 

[Howard]

Are we to assume that "reach" means to touch the bottom first?

 

[Cattlegod]

uhh guys, it says to ignore air resistance in the question: "no friction" air resistance is a form of friction.

they would both hit the bottom at the same time and the cylinder will not roll.

 

[mugs]

Originally posted by: Demon-Xanth
If there were absolutely NO friction, yes. They would both slide down the ramp.

Usually the question is a hoop and a disk of equal weight

Right, the question is wrong where it says it would roll.

 

[PlatinumGold]

shape and where they are lined up will determine which hits ground first.

if the block lines up with where the cylinder touches the ramp, then cylinder reaches bottom first. if the block is lined up with the cylinder where the leading edges are the same, than the block hits first.

either way, both will travel at the same speed.

 

[Wheatmaster]

Originally posted by: nourdmrolNMT1
ok, you guys complained enough.

here is the full question from my test.

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, (ignore friction)

A. the cylinder will reach bottom first
B. the block will reach the bottom first with the greater kinetic energy.
C the block will reach the bottom first.
D. the cylinder will reach the bottom with the greater kinetic energy
E. both the block and the cylinder will reach the bottom at the same time.

moment of inertia buddy! moment of inertia!!!

 

[Armitage]

Originally posted by: Wheatmaster

Originally posted by: nourdmrolNMT1
ok, you guys complained enough.

here is the full question from my test.

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, (ignore friction)

A. the cylinder will reach bottom first
B. the block will reach the bottom first with the greater kinetic energy.
C the block will reach the bottom first.
D. the cylinder will reach the bottom with the greater kinetic energy
E. both the block and the cylinder will reach the bottom at the same time.

moment of inertia buddy! moment of inertia!!!

read the thread buddy! read the thread!!!