Awarehouse worker uses a forklift to raise a crate of pickles on a platform to a height 2.75 m above the floor. the combined mass of the platform and the crate is 207 kg.
if the power expended by the forklift is 1440 w, how long does it take to lift the crate?

a) 37.2
b) 5.81
c) 3.87
d) 18.6
e) 1.86

correct option is c) 3.87

Explanation:

given data

height = 2.75 m

mass = 207 kg

power = 1440 W

to find out

how long it take to lift the crate

solution

we know that work done in raising the crate & platform

so

work done = change in potential energy that is

work done = mgh    ....................1

work done  =207 ×9.81 × 2.75

work done = 5584.3425 J

and we know power that is

power =     .............2

1440 =

time = 3.878 s

so correct option is c) 3.87

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.

see earlier answer