When the child jumps onto the merry-go-around the moment of inertia of the system changes. If we consider the child to be point-like mass then its moment of inertia would be:

We get the new moment of inertia by simply adding the child's moment of inertia to the old moment of inertia.

Since there is no force mention we must assume that angular momentum is conserved.

When we plug in all the numbers we get:
Answer:
60 ÷ 5= 12 is the speed, hope it helps
Answer:
C. X: Allows current to flow into the commutator
Y: Conducts current to the armature and reverses direction of current
Explanation:
Carbon brush is a motor brush that acts as the conducting block for current between the stator and the rotor of a motor.It is made of carbon blocks.The brush is held in place using a spring that ensures its contact position with the commutator.The commutator prevents the torque on the motor from reversing whenever the coil is rotating in the magnetic field.
Answer:
<em>a. The rock takes 2.02 seconds to hit the ground</em>
<em>b. The rock lands at 20,2 m from the base of the cliff</em>
Explanation:
Horizontal motion occurs when an object is thrown horizontally with an initial speed v from a height h above the ground. When it happens, the object moves through a curved path determined by gravity until it hits the ground.
The time taken by the object to hit the ground is calculated by:

The range is defined as the maximum horizontal distance traveled by the object and it can be calculated as follows:

The man is standing on the edge of the h=20 m cliff and throws a rock with a horizontal speed of v=10 m/s.
a,
The time taken by the rock to reach the ground is:


t = 2.02 s
The rock takes 2.02 seconds to hit the ground
b.
The range is calculated now:

d = 20.2 m
The rock lands at 20,2 m from the base of the cliff
2 is the answer have a nice day <3