Question

A frictionless pendulum clock on the surface of the earth has a period of 1.00 s. On a distant planet, the length of the pendulum must be shortened slightly to have a period of 1.00 s. What is true about the acceleration due to gravity on the distant planet?AnswerWe cannot tell because we do not know the mass of the pendulum.The gravitational acceleration on the planet is slightly less than g.The gravitational acceleration on the planet is slightly greater than g.The gravitational acceleration on the planet is equal to g.

Answer 1

The gravitational acceleration on the planet is slightly less than g.

Step-by-step explanation:

The period of a pendulum is given by:

`T=2\pi \sqrt{(L)/(g)}`

where

L is the length of the pendulum

g is the acceleration due to gravity

The formula can also be rewritten as

`g=((2\pi)/(T))^2 L` (1)

In this problem, we have a pendulum which has a period of T=1.00 s on Earth. The length of the same pendulum must be shortened on the distant planet to have the same period of T'=1.00 s: this means that the length of the pendulum on the distant planet, L', is shorter than the length of the pendulum on Earth, L

`L'<L`

By looking at formula (1), we see that g (the gravitational acceleration) is directly proportional to L. therefore, if L is shortened on the distant planet, it means that also the value of g is lower than on Earth:

so, the correct answer is

The gravitational acceleration on the planet is slightly less than g.