I-5) Two wheels each rotating freely in opposite directions are brought in conta
ID: 1796271 • Letter: I
Question
I-5) Two wheels each rotating freely in opposite directions are brought in contact of each other. Which is the true statement? A) They immediately stop rotating when they touch. B) The angular momentum is conserved C) The rotational kinetic energy is conserved. D) The torques subtract C1-10 When a solid rigid object rotates about a fixed axis, what is true about all the points in the object? A) They all have the same tangential speed B) They all have the same angular acceleration. C) They all have the same tangential acceleration. D) They all have the same radial acceleration. 1-6) C1-1 I-7) Two children, Ahmed and Jacques, ride on a merry-go-round. Ahmed is at a greater distance from the axis of rotation than Jacques. Which of the following are true statements? A) Jacques has a greater angular speed than Ahmed. B) Jacques and Ahmed have the same angular speed. C) Jacques has a smaller angular speed than Ahmed. D) There not way to tell without knowing the masses of the two children C1-2 Consider a uniform hoop of radius R and mass M rolling without slipping. Which is larger, its translational kinetic energy or its rotational kinetic energy? A) Translational kinetic energy is larger B) Rotational kinetic energy is larger C) Both are equal. D) You need to know the speed of the hoop to tell. 1-8) C1-3 A person sits on a freely spinning lab stool that has no friction in its axle. When this person extends her arms A) her moment of inertia decreases and her angular speed increases. B) her moment of inertia decreases and her angular speed decreases. C) her moment of inertia increases and her angular speed increases. D) her moment of inertia increases and her angular speed decreases. 1-9) E) her moment of inertia increases and her angular speed remains the same C1-4 1-10) When an unbalanced external torque is applied, an object will A) always accelerate in a circle. B) always have constant angular momentum. C) always rotate with constant angular velocity. D) always stop turning due to the torque on it. C1-5Explanation / Answer
1-5
when two freely rotating in oppisite directions wheels are brought in contact each other then
from the given options the torques are subtract , resulting the slowing down of the wheels
a. they may not immediately stop rotating when they touch , depends on the conditions like if they are moving with the same speed it happens
b. angular momentum may not conserved
c. rotational k.e does not conserved
d. True ---->> Ans
1-6
when a solid rigid object rotates about a fixed axis then all the particles have
we know that the body is rigid and can not be deformed so , every point has same angular acceleration and angular speed
the answer is B)
1-7
merry - go - round
Ahmed is at greater distance from the axis of rotation, than Jacques
the angular momentum L = I*W
L = m*r^2 *w
if both are of same mass and moving with same angular velocity then Ahmed is at larger distance from axis of rotation so
and we can answer if the mass is known so the answer is option D)
1-8
Hoop at rolling without slipping
the translational k.e = 0.5*m*v^2 and rotational k.e = 0.5*I*W^2
where V= R*W , condition for rolling without slipping
I = M*R^2 , rotational k.e = 0.5*M*R^2*V^2/R^2 = 0.5*M*V^2
both the kinetic energies are same
1-9 D
when a person on freely spinnnig stool , extends her arms then the angular momentum conservation
L = I*w
Li = Lf
from the options
the momentof inertia increases and angular speed decreases is answer