An ideal pendulum is often discussed when studying simple harmonic motion.

what are the conditions needed for an ideal pendulum? check all that apply.

gravitational force acts to pull the pendulum’s mass down.
the mass of the rod of the pendulum is evenly distributed along the rod.
the pivot on which the pendulum swings is frictionless.
the pendulum swings through its equilibrium position as a result of inertia.
tension acts downward on the pendulum’s mass.

When studying simple harmonic motion, the conditions that are needed for an ideal pendulum are;

Gravitational force acts to pull the pendulum’s mass down.

The pivot on which the pendulum swings is friction less.

The pendulum swings through its equilibrium position as a result of inertia

Explanation:

A simple pendulum consists of a point mass that is suspended on a string.The mass of the string is assumed to be very small with no effect to the process.At the point of swing, friction should be less or zero.The point mass is affected by gravity that pulls its down.This force can be expressed as;

F=mgwhere m is mass of object suspended and g is the acceleration due to gravity.

When a displacement is done on the mass from its equilibrium position, an angle Ф is formed.The force needed to bring it back to equilibrium position will be;

F= -mgSinФ

For small angles SinФ=Ф

Thus F= - mgФ

1, 3, 4

Explanation:

took the test on edge.

d. air pressure decreases as altitude increases.

it is given that trillions of microbes make up to 1% to 3% of the body mass.

let's take average of this percentage: 2%

consider the average mass of the human body as 70 kg.

then, trillions of microbes would have mass  

therefore, 100 trillion micro-organisms would weigh:

this is an approximate value and could change depending on the mass of the human body and percentage of the microbes present in it.

average mass per microorganism =