Answer:
a) 
b) 
Explanation:
Let's find the radius of the circumference first. We know that bob follows a circular path of circumference 0.94 m, it means that the perimeter is 0.94 m.
The perimeter of a circunference is:


Now, we need to find the angle of the pendulum from vertical.


Let's apply Newton's second law to find the tension.

We use centripetal acceleration here, because we have a circular motion.
The vertical equation of motion will be:
(1)
The horizontal equation of motion will be:
(2)
a) We can find T usinf the equation (1):

We can find the angular velocity (ω) from the equation (2):

b) We know that the period is T=2π/ω, therefore:

I hope it helps you!
B is the answer for your question the answer is b an elevator slowing down
Explanation:
a) Power = work / time = force × distance / time
P = Fd/t
P = (85 kg × 9.8 m/s²) (4.6 m) / (12 s)
P ≈ 319 W
b) P = Fd/t
0.70 (319 W) = (m × 9.8 m/s²) (4.6 m) / (9.6 s)
m = 47.6 kg
Noble gases are not highly reactive