Im pretty sure the answer is c; velocity is usually measure by a vector :)
Answer:
B. It begins to rotate counterclockwise
Explanation:
It can happen that the merry-go-round remains at rest in the case when the person is standing on the axle of the merry go round whose axis is fixed to some rigid support, but here the person is standing at the center of the merry-go-round not at the axle hence the according to the conservation of angular momentum. Angular momentum is given as:

for the conservation of momentum

where:
moment of inertia of the merry-go-round
angular velocity of the merry-go-round
moment of inertia of the bicycle wheel
angular velocity of the wheel
As the person tries to stop the wheel which is rotating then the person feels an opposing force which tries to moves the whole system in its direction.
Answer:
1. The number of turns on the secondary output is 18
2. The root mean square power delivered to the transformer is 48 Watts.
Explanation:
A transformer is an electronic device that can be used for increasing or decreasing the value of a given voltage. It consists of primary coils and secondary coil of a definte number of turns. When voltage flows in the primary coil, it induces voltage in the secondary coil. The two types are: step-up and step down transformers.
1. For a given transformer,
= 
where
is the value of the induced voltage in the secondary coil,
is he voltage in the primary coil, and
is the number of turns of the secondary coil,
is the number of turns in the primary coil.
From the question,
= 9.0 V,
= 120 V,
= 240,
= ?
So that,
= 
= 
= 18
The number of turns on the secondary output is 18.
2.
=
× 
= 0.4 × 120
= 48 W
The rms power delivered to the transformer is 48 Watts.
Answer:
Using 3 periods to get an accurate reading:
3T = (6.40 S - 0.90 s) = 5.50 S So, T = 1.83 s
m = 0.250 kg
Using algebra:
k=
=
=2.95kg/sec