Question

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 the the merry-go-round? (b) (10 pts) What is the new angular speed, in rad/s, of the merry-go-round? (c) (5 pts) How many seconds will it take for the system to cover 5.0 complete revolutions? (d) (10 pts) What is the total kinetic energy of the system before and after the child hops on the the merry-go-round?

Answer #1

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 playground merry-go-round of radius R = 1.60 m has a
moment of inertia I = 255 kg·m2 and is rotating
at 11.0 rev/min about a frictionless vertical axle. Facing the
axle, a 25.0 kg child hops onto the merry-go-round and manages to
sit down on its edge. What is the new angular speed of the
merry-go-round?

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 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 has a radius of 3m and a moment of
inertia of 1500 kg m^2. 4 kids sit at the outer edge with each kid
having a mass of 20 kg, and the merry-go-round spins at 1.75 rad/s.
If 2 of the 4 kids move to a position that is 0.3m from the center
of the merry-go-round, what is the new rotational speed of the
merry-go-round? No energy is lost to friction and the children are
point masses.

A playground merry-go-round (of mass 123 kg and radius 1.90 m)
is rotating with an angular velocity of 4.42 rad/s. A 23.7 kg
child, initially at rest, suddenly jumps on the merry-go-round by
grabbing onto its outer edge. How much kinetic energy (in J) is
lost in this inelastic collision?

A 20-kg child running at 2.0 m/s jumps onto a playground
merry-go-round that has inertia 180 kg and radius 1.6 m. She is
moving tangent to the platform when she jumps, and she lands right
on the edge. Ignore any friction in the axle about which the
platform rotates. What is the rotational speed of the
merry-go-round and the child if the merry-go-round started from
rest? Express your answer with the appropriate units.

A playground merry-go-round has a mass of 120 kg and a radius of
1.80 m and it is rotating with an angular velocity of 0.600 rev/s.
What is its angular velocity (in rev/s) after a 28.0 kg child gets
onto it by grabbing its outer edge? The child is initially at
rest.
rev/s

A playground merry-go-round has a radius of 3.0 m and a
rotational inertia of 600 kg-m^2. When the merry-go-round is at
rest, a 20-kg child runs at 5.0 m/s along a line tangent to the rim
and jumps on. The angular velocity of the merry-go-round is
then:
.45 rad/s
1.2 rad/s
.38 rad/s
.56 rad/s
.71 rad/s

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 2 minutes ago

asked 17 minutes ago

asked 17 minutes ago

asked 39 minutes ago

asked 44 minutes ago

asked 56 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 2 hours ago

asked 2 hours ago