Answer:
4.78 second
Explanation:
given data
vertical cliff = 41 m
height = 112 m
solution
we know here time taken to fall vertically from the cliff = time taken to move horizontally ..........................1
so we use here vertical component of ball
and that is accelerated motion with initial velocity = 0
so we can solve for it as
height = 0.5 × g × t² ........................2
put here value
112 = 0.5 × 9.8 × t²
solve it we get
t² = 22.857
t = 4.78 second
ball thrown horizontally from the top of the cliff in 4.78 second
Answer:
Only (I) is true
i) Mass is conserved during a chemical reaction.
Answer:
the decay of half of the nuclei only a half-life has passed
, b) in rock time it is 1 108 years
Explanation:
The radioactive decay is given by
N = N₀
If half of the atoms have decayed
½ N₀ = N₀
½ =
₀
Ln 0.5 = - λ t
t = - ln 0.5 /λ
The definition of average life time is
= ln 2 / λ
λ = ln 2 / 
λ = 0.693 / 100 10⁶
λ = 0.693 10⁻⁸ years
We replace
t = -ln 0.5 / 0.693 10⁻⁸
t = 10⁸ years
We see that for the decay of half of the nuclei only a half-life has passed
b) in rock time it is 1 108 years