Answer:
Option (c) : 20°C
Explanation:

T(final) = 500* 10 + 100*70/600 = 20°C
force=mass × acceleration
mass=force ÷ acceleration
acceleration=force ÷ mass
The period of one full swing depends on the length of the pendulum and on gravity. The period of each full swing would be longer on the moon, with less gravity.
The rotation of the plane of the swings doesn't depend on the length of the string OR on gravity. It only depends on the latitude of the place where the pendulum hangs, and the rotation period of the body it's located on.
On Earth, it's (24 hours)/(sine of latitude).
On the moon, it would be (27.32 days)/(sine of latitude).
Answer:
The acceleration of Abbie is half of the Zak's.
Explanation:
The centripetal acceleration of an object on a circular path is given by :

Two children are riding on a merry-go-round that is rotating with a constant angular speed. Let
is distance of Abbie from the merry-go-round and
is distance of Zak's from the merry-go-round. Acceleration of Abbie is :
...... (1)

Acceleration of Zak's is :
.......(2)

Dividing equation (1) and (2) we get :

So, the acceleration of Abbie is half of the Zak's.