Question

A stone falls from a building and reaches the ground 2.5 seconds later.How high is the building

Answer 1

given:
g=9.8m/sec²
u=0m/s
t=2.5sec

h = ut +½ gt²
h = 0 × 2.5 + ½ × 9.8 × (2.5)²
h = 0 + 4.9 × 6.25
h = 30.625 m

Answer 2

"Newton’s 2nd equation of motion

S=ut+1/2(a* t²)

here, u is initial velocity of object,

t is time taken,

a is acceleration of the object ,

And lastly S is the distance covered

u is 0

Acceleration of the object is 9.8m/sec²

Time taken is given and that is t=2.5s

Applying the equation we get,

S= 1/2(a*t²)

(Since u is 0 )

Putting the values we get,

S= 1/2(9.8*2.5²)

S= 4.9(6.25)

S= 30.625 m

The height of the building is 30.625 meters

"