Question

x.Hm

I just need help in the three questionI figure the last question

1)Consider an oxygen molecule (O2) rotating inthe xy plane about the z axis. The axis

passes through the center of the molecule,perpendicular to its length. The mass of each

oxygen atom is 2.66 x 10

-26 kg, and at room temperature the average separation between

the two atoms is

d=1.21 x 10-10 m (the atoms are treated as point masses).a) Calculate

the moment of inertia of the molecule about the zaxis. b) If the angular speed of the

molecule about the

z axis 4.60 x 1012 rad/s, what is its rotational kineticenergy?

Answer: a) 1.95 x 10

-46 kg.m2 b) 2.06 x 10-21 J

2) A wheel rotates with a constant angularacceleration of 3.50 rad/s2. If the angular speed

of the wheel is 2.00 rad/s at

ti = 0, a) through what angle does the wheel rotate in2.00 s?

Answer a) 6300

3)A uniform rod of length L and mass M is free to rotate on africtionless pin passing

through one end as shown in question 4 below. Therod is released from rest in the

horizontal position. a) What is its angular speedwhen it reaches its lowest position?

b) Determine the linear speed of the center ofmass and the linear speed of the lowest

point on the rod when it is in the verticalposition.

Answer: a)

L

3g b) Center of mass speed =3gL

2

1 ;

Linear speed of the lowest point =3gL

(Hint, use mechanical energy conservation)

4 A uniform rod of length L and mass M is attached at one endto a frictionless pivot and is

free to rotate about the pivot in the verticalplane, as shown in Figure below. The rod is

released from rest in the horizontal position. a)What is the initial angular acceleration of

the rod and b) the initial linear acceleration ofits right end? Answer: a)

Answer: a)

L

3

g b) Center of mass speed = 3gL

2

1 ;

Linear speed of the lowest point =3

gL

(Hint, use mechanical energyconservation)

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