Answer:
The new value of g 
Explanation:
Mass =290 g
Spring size = 40 cm
The size of spring after streches = 23 cm
Pulling the mass down at = 11.7 cm
The stopwatch shows the number of oscillations in 17.7 s = 9 osscillations.
The oscillation frequency is independent to g.

The amount of spring stretch due to the hanging mass, x, is dependent on g.

Therefore, the new value of g 
Explanation:
Note that from Newton's law of motion:
the sum of the positive horizontal forces on an object equals the sum of the negative horizontal forces therefore, the net force on the object is zero.
Also, velocity is constant, acceleration is zero.
F = m × a
= 0 N
Answer: A) length of string.
Conduction is the transfer of energy by collusion between the atoms and molecules in a material.