Premium A student releases a marble from the top of a ramp. The marble increases speed
while on the ramp then continues across the floor. The marble travels a total of
150cm in 4.80s.
What was the marble's final speed?

31.25 cm/sec

We are given:

Distance travelled = 150 cm

Time taken = 4.8 seconds

Final Speed of the Marble:

Speed of the marble = Distance travelled / Time taken

Speed of the marble = 150 / 4.8

Speed of the marble = 31.25 cm/sec

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.

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 =