3. Automobile companies often test the safety of cars by putting them through crash tests to observe the integrity of the passenger compartment. If 1100kg car is sent toward a cement wall with a speed of15 m/s, an impact force of 185,000 N stops the car, how long does it take before the car is brought to a stop?​

Time taken for car to stop = 0.89 seconds (Approx.)

Explanation:

Given:

Mass of car = 1100 kg

Speed of car = 15 m/s

Impact force = 185,000 N

Find:

Time taken for car to stop

Computation:

Change in momentum of car = M(v) - M(u)

Change in momentum of car = 1100(0) - 1100(15)

Change in momentum of car = -16,500

Time taken for car to stop = I Change in momentum of car I / Impact force

Time taken for car to stop = I-16,500I / 185,000

Time taken for car to stop = 0.89 seconds (Approx.)

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.