What is the potential energy of a falling rock if it has a mass of 64 kg and fell from a height of 54 m

P.E (Potential Energy) = 33868.8 J

Explanation:

The formula to calculate Potential energy is:

PE = mgh

where PE = potential energy

m = mass of an object

g = acceleration due to gravity

h = height of the object

Here, m = 64 kg

         g  =  9.8

         h  = 54 m

So, substituting the values in the formula:

PE = mgh

    = 64 × 9.8 × 54

    = 33868.8 J

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.