Cory said his science textbook down on the roof of his car as he was getting in, and he forgot it there. As he was driving at 30 mph, his car suddenly crashed and very quickly came to a stop. Assuming that the force of friction on the book is negligible, what was the speed of the science textbook the moment after the crash?

The speed of the book was 30 mph the moment after the crash.

Explanation:

Here we invoke Newton's 1st law which says that when no forces acting are on a body, it will not change its motion—if its a rest, it will remain at rest; if it is moving with constant velocity, it will keep moving with constant velocity.

Before the crash happened, both the car and the book are going at 30mph, After the crash, the car stopped, and since there was no frictional force on the book, Newton's 1st law demands that the book keeps going at the velocity it has; therefore, the book will continue moving at 30mph after the crash.

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.

the answer to this is proletariats.

hope this : )