Acceleration is a vector quantity that takes into account the changes in either the direction or the velocity or both. From the choices given, I go with choice number 2 where the body moves in a circular motion; thus, causing changes in its direction from time to time.
1. It has a negative value
Most common are destructive tests, such as stress, fatigue and micro sectioning tests. There are also methods that allow non-destructive testing (NDT), so the material can be still be used after testing. Common methods are ultrasonic, X-ray, HF Eddy Current, Radio Wave testing or thermography.
Answer:
The period of the system of ladder and woman, T = 2.5 seconds
Explanation:
Mass of the ladder, 
Mass of the artiste, 
Length of the ladder, L = 42.0 kg
The total moment of inertia can be calculated using the equation:

D = L/2 = 3/2
D = 1.5 m
The frequency of the system of ladder and woman follows that of a physical pendulum which can be given by the equation:

The period of the system of ladder and woman is given by:
T = 1/f
T = 1/0.4
T = 2.5 seconds