Question

An object is thrown with a horizontal velocity of 25 m/s from a cliff of 180 m height . How long does it take for object to reach ground ? plzz answer fast

Answer 1

Answer:

Height of the cliff h

1

=20m

Velocity of projectile V=30m/s

Initial upward velocity v

y

=Vsinθ=30×sin30

∘

=15m/s.

Horizontal velocity, v

x

=Vcosθ=30cos30

o

m/s

Time taken to reach maximum height, t

1

=

g

V

y

=

10

15

=1.5sec.

Height above the cliff h

2

=

2g

v

y

2

=

2×10

15

2

=11.25m

Therefore, the maximum height, h

max

=h

1

+h

2

=20+11.25=31.25m.

Time taken to free fall from max height, t

2

=

g

2h

max

=

g

2×31.25

=2.5sec.

Thus, the total time taken during the entire flight t

total

=t

1

+t

2

=1.5+2.5=4sec

Total horizontal distance covered R=v

x

t

total

=30×cos30

∘

×4=60

3