Auniform ladder is 10 m long and weighs 200 n. in fig. 12-78, the ladder leans against a vertical, frictionless wall at height h = 8.0 m above the ground. a horizontal force f → is applied to the ladder at distance d = 2.0 m from its base ( measured along the ladder). (a) if force magnitude f = 50 n, what is the force of the ground on the ladder, in unitvector notation? (b) if f = 150 n, what is the force of the ground on the ladder, also in unit-vector notation? (c) suppose the coefficient of static friction between the ladder and the ground is 0.38; for what minimum value of the force magnitude f will the base of the ladder just barely start to move toward the wall?

d

explanation:

v=uf/(u-f)

= 5.10/(5-10) convex lens has positive focal length

=50/-5

=-10 cm (formed at other side)

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 =

the moving of the box is a result of centripetal force. think of that  as a car or a truck in this case creates a turn, the force of friction performing upon the turned wheels of the car runs centripetal force obligatory for circular motion for the things inside it.