A tennis ball is dropped from 1.7 m above the ground. It rebounds to a height of 0.955 m.

With what velocity does it hit the ground?

The acceleration of gravity is 9.8 m/s^2 (Let

down be negative.)

Answer in units of m/s

With what velocity does it leave the ground?
Answer in units of m/s.

If the tennis ball were in contact with the
ground for 0.0135 s, find the acceleration
given to the tennis ball by the ground.
Answer in units of m/s^2

two charges are fixed in place on the x-axis as shown. the charge at x = 0 is negative and has magnitude q = 2 μcoulombs (1 μcoulomb = 10-6 coulombs). the charge at x = d, (d = +12 cm), is positive and has magnitude q = 4 μcoulombs. find a point x = xo along the x-axis at which the electric field is zero.

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 =