Final answer:
To make the pendulum tick once a second, its length should be approximately 0.249 meters.
Step-by-step explanation:
In order for the grandfather clock to tick once a second, the length of the pendulum must be adjusted to match the desired frequency. The period of a simple pendulum is given by the equation T = 2pi*sqrt(L/g), where T is the period, L is the length of the pendulum, and g is the acceleration due to gravity. To find the length of the pendulum needed for a period of 1 second, we can rearrange the equation as L = (T^2*G)/(4pi^2), where G is the acceleration due to gravity.
Let's substitute the values into the equation:
L = (1^2*9.8)/(4*3.14^2) = (9.8)/(4*9.87) = 0.249 m
So, the length of the pendulum must be approximately 0.249 meters for the ticks to occur once a second.