Question

- A merry-go-round at a playground is rotating at 6.0 rev/min. Four children jump on and increase the moment of inertia of the merry-go-round by 30%.

What is the new rotation rate? What torque must be applied by the merry-go-round’s motor in order to restore the initial rotation rate within 30 seconds or 0.5 minutes?

Answer #1

If you and your children are on a rotating playground
merry-go-round wheel and you jump off, what happens to the rate of
spin of he wheel? Assume it has a mass of 200 kg, a radius of 2
meters, and is roughly a disk of solid material initially rotating
at 1 turn in 3 seconds. Let your mass be 65 kg and find the new
rate of rotation after you jump off.

A playground merry-go-round of radius R = 2.6 m has a moment of
inertia of I = 200 kg*m^2. and is rotating at a rate of ω
= 11 rev/min around a frictionless vertical axis. Facing the axle,
a 39 kg child hops onto the merry-go-round and manages to sit down
on the edge. What is the new angular speed of the merry-go-round
(in rev/min)

A playground merry-go-round of radius 1.9 m has a moment of
inertia 139 kg.m2 and is rotating at 9 rev/min about a frictionless
vertical axle. Facing the axle, a 27 kg child hops onto the
merry-go-round, and manages to sit down on the edge. What is the
new angular speed of the merry-go-round?

A 5.0-m radius playground merry-go-round with a moment of
inertia of 2000 kg?m2 is rotating freely with an angular speed of
3.0 rad/s. Two people, each having a mass of 60 kg are standing
right outside the edge of the merry-go-round. One person radially
steps on the edge merry-go-round with negligible speed and the
angular speed changes to ?1. A few seconds later, the second person
radially steps on the merry-go-round with negligible speed but at
distance of 4.0 m...

A 5.0-m radius playground merry-go-round with a moment of
inertia of 2000 kg?m2 is rotating freely with an angular speed of
3.0 rad/s. Two people, each having a mass of 60 kg are standing
right outside the edge of the merry-go-round. One person radially
steps on the edge merry-go-round with negligible speed and the
angular speed changes to ?1. A few seconds later, the second person
radially steps on the merry-go-round with negligible speed but at
distance of 4.0 m...

A playground merry-go-round with a moment of inertia of 300 kg
m2 is rotating with no friction at an angular velocity
of 2.3 rad/s. Sharon, whose mass is 70 kg, runs and jumps on the
merry-go-round in such a way that after she jumps on it the
merry-go round stops. How fast, in m/s was she running if the
merry-go-round had a radius of 2.5 m? Enter only the numerical
value of your answer to 2 significant figures. Do not...

A playground merry-go-round has a moment of inertia of 600 kg
m2. When the merry-go-round is at rest, a 20 kg boy runs
at 5.9 m/s along a line tangential to the rim and jumps on, landing
on the rim a distance of 3.0 m from the rotation axis of the
merry-go-round. The angular velocity of the merry-go-round is
then:
A.1.2 rad/s
B.0.38 rad/s
C.0.45 rad/s
D.0.56 rad/s
E.0.72 rad/s

A playground merry-go-round of radius ? = 2.0 m has a moment of
inertia ? = 250 kg ⋅ m^2 is rotating at 15 rpm about a
frictionless, vertical axle. Facing the axle, a 25-kg child hops
onto the merry-goround and manages to sit down on the edge. (a) (10
pts) What is the total angular momentum of the
‘merry-go-round-child’ system before and after the child hops on
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Torques and Angular Momentum
1. A 250 kg playground merry-go-round has a radius of 2.0m and
can be approximated as a disk.
A.Find the moment of inertia of the merry-go-round.
B.A 30.0 kg child applies 20 N tangential force for 10 seconds
and then jumps on the edge while moving at the same speed as the
merry-go-round. Find the angular speed of the merry-go-round and
the child.
C.How much work did the child do on the merry-go-round?
D.How much average...

. In a park, four children are riding on a merry-go-round with a
radius of 2.2 m and a mass of 300 kg. The children have an average
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the center of the merry-go-round. The merry-go-round is rotating at
a speed of 0.25 revolutions per second. The children then move
inwards towards the center of the merry-go-round, so they are
standing 0.5 m from the center. What...

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