17. A body is released from position A as shown in figure. The speed of body at position B is
[NCERT Pg. 121]
22
50 m
- В
10 m
]
(1) 10 m/s
(2) 10/2 m/s
(3) 20 m/s
(4) 2012 m/s​

Potential energy at A is mgh1 = 50mg

Energies at point B are kinetic and potential.

Potential energy at B is mgh2 = 10mg

Kinetic energy at B is 1/2mv^2

Energy at A = Energy at B

mgh1 = mgh2 + 1/2mv^2

50mg = 10mg + 1/2mv^2

1/2mv^2 = 40mg

1/2v^2 = 40g

v^2 = 40 x 10 x 2

v^2 = 800

v =✓800 m/s

v = 28.284

HOPE IT HELPS!!!

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.