Question

Please answer this question of physics class 9

Answer 1

Explanation:

$\red{\boxed{\rm \underline{Given}}}$

u = 80 m/s

v = 0 m/s

s = 1500 m

$\red{\boxed{\rm \underline{To \: Find}}}$

We have to find retardation and the time taken from the aeroplane to come to rest.

$\red{\boxed{\rm \underline{Solution}}}$

i) Here we have the values of intial velocity, final velocity, Displacement and we have to find the acceleration,

To find the acceleration we can use the third equation of motion, i.e v² - u² = 2as

Applying third equation of motion,

0² - 80² = 2a(1500)

-6400 = 3000a

-64 = 30a

a = -64/30 = -32/15 = -2.133 m/s²

Therefore,

Retardation of the aeroplane = 2.133 m/s²

ii) Here we have the values of intial velocity, final velocity, acceleration and we have to find the time

To find the time taken we can use the first equation of motion, i.e v = u + at

Applying the first equation of motion,

0 = 80 - 2.133t

80 = 2.133t

t = 37.505 s

$\red{\boxed{\rm \underline{Equation \: of \: motions}}}$

i) v = u + at

ii) s = ut + at²/2

iii) v² - u² = 2as