- #1
Likith D
- 65
- 1
This post lacks the homework template because it was originally posted in a non-homework forum.
A rod of mass M (=4m) and length L is placed over a smooth horizontal table. One end of rod is attached with a block of mass m through a light string as shown in the figure. The pulley is friction less and light. the acceleration of com of rod at the given instant is (g = acceleration due to gravity)
a) g/2
b) g/8
c) g/5
d) 2g/5
that does not make sense, because i think the force on com is net force on object = mg = Ma (force of com by Newton's law)
(M = mass of com = 4m)
therefore, a = mg/M = mg/4m = g/4 which is none of the above
note:
1. Ma = mg is true even if the body rotates
2. It's reasonable to have no friction, since it is smooth
3. The rod does not seem to have any of it's points fixed to table to revolve around of
4. There was no use of the fact that force was perpendicular to rod as in the figure
a) g/2
b) g/8
c) g/5
d) 2g/5
that does not make sense, because i think the force on com is net force on object = mg = Ma (force of com by Newton's law)
(M = mass of com = 4m)
therefore, a = mg/M = mg/4m = g/4 which is none of the above
note:
1. Ma = mg is true even if the body rotates
2. It's reasonable to have no friction, since it is smooth
3. The rod does not seem to have any of it's points fixed to table to revolve around of
4. There was no use of the fact that force was perpendicular to rod as in the figure