A2000-kg car traveling at 40m/s hits a wall with a force of 40,000n and comes to a stop what was the impact time? a-0.5s b-2s c-400s d-800s

Option (B)

Explanation:

mass of car, m = 2000 kg, initial velocity of car, u = 40 m/s,

Force, F = 40,000 N, Final velocity, v = 0 m/s

Let the impact time be t.

By use of Newton's second law

F = m a

where, a be the acceleration and m be the mass.

40000 = 2000 x a

a = 20 m/s^2

Acceleration is negative because the car is stopped.

Use first equation of motion,

v = u + a x t

0 = 40 - 20 x t

t = 2 second

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.

i would say