Answer:
l = 0.8 m
gMars = 3.65 m/s2
Step-by-step explanation:
The period of a pendulum depends on the length of it and the acceleration of gravity according to this equation:

If the pendulum has a period of 1.8s on Earth, the length must be:

If it has a period of 2.94 s on Mars, the gravity must be:
