A pick-up truck with two passengers weighs about 14000 N. In good driving conditions around a curve, the maximum friction with the road is equal to the truck's weight. What is the minimum safe curve radius that the truck could negotiate at 28.9 m/s

85.14 m

Explanation:

Let g = 9.81 m/s2. We can find the truck mass from its weight

m = W/g = 14000 / 9.81 = 1427 kg

So if the maximum friction could be the truck weight, which is F = 14000N, then that would also be the maximum centripetal force it could be. According to Newton 2nd law of motion, the maximum centripetal acceleration the truck can have when traveling at a curve is

a = F / m = 14000 / 1427 = 9.81 m/s2

By applying the following formula we can find the minimum safe radius R of the curve when traveling at speed of 28.9 m/s

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.