Calculate the force of friction (ff) for a 5 kg aluminum block being pulled with constant velocity (uniform motion),up a steel plank that is at a 30 degree angle to the horizontal.

24.5 N

Explanation:

Calculate the Force of Friction (Ff) for a 5 kg aluminum block being pulled with constant velocity (uniform motion),up a steel plank that is at a 30 degree angle to the horizontal.

the frictional is the force that opposes the motion of two surfaces in contact

frictional force should be balanced by one component of weight of the block along the plane.  resolving the weight to the the vertical component

∴f = mgsin30° = 5×9.8×0.5 = 24.5 N.

mass=the quantity of matter in a body 5kg

g=acceleration due to gravity m/s^2

their crystal patterns have been disrupted by stress

answer: at 24 february, 2014 the population gets twice of its initial population.

explanation:

since we have given that

the population for alpha city, t years after january 1, 2004 is given as

first we find out the initial population, i.e. t=0,

so, our quadratic equation becomes,

according to question, we have said that if the population has twice its initial population, then it becomes

so, time taken to reach this above mentioned population is given by

now, we know that time can't be negative so, we take t=9.149 years.

hence, at 24 february, 2014 the population gets twice of its initial population.