1.A test rocket is launched vertically from ground level (y = 0 m), at time t = 0.0 s. The rocket engine provides constant upward acceleration during the burn phase. At the instant of engine burnout, the rocket has risen to 49 m and acquired a velocity of 30 m/s How long did the burn phase last 2.What is the max height the rocket will reach

1. t = 3.27 seconds

2. y = 147.3 m

Explanation:

Newton's Laws of Motions.

y = v₁t + 1/2 at²

a = (v₂-v₁)/t

where

y = the vertical distance travelled

v₁ = the initial velocity

v₂ = the final velocity

t = the time

a = the acceleration

final velocity is equal to 0.

So, v₂ = 0.

a = (v₂-v₁)/t

a = (0-30)/t

a = -30/t

plugin values into the first equation:

y = v₁t + 1/2 at²

49 = 30t + 1/2 (-30/t)t²

49 = 30t -15t

49 = 15 t

t = 49/15

t = 3.27 seconds

2.

y = v₁t + 1/2 at²

a = -30/3.27

a = 9.2

y = 30(3.27) + 1/2(9.2) 3.27²

y = 147.3 m

answer; i believe that the correct answer is (d) a very small amount of mass

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.