If a block of wood dropped from a tall building has attained a velocity of 78.4 m/s how long has it been falling
1 answer:
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Answer:
1817.448 m
Explanation:
Given:
Initial acceleration = 2.24 m/s²
Time for acceleration = 10 s
From Newton's equation of motion
v = u + at
here v is the final velocity after the acceleration
v = 0 + 2.24 × 10 = 22.4 m/s
thus,
the displacement during acceleration
From Newton's equation of motion
where,
s is the distance
u is the initial speed = 0 m/s as starting from rest
a is the acceleration
t is the time
on substituting the respective values, we get
or
s₁ = 112 m
for case 2
time = 1.25 minute = 1.25 × 60 = 75 seconds
displacement, s₂ = v × t = 22.4 × 75 = 1680 m
for the case 3
acceleration = - 9.86 m/s²
now,
the final velocity for the second case is the initial velocity for this case
thus,
or
s₃ = 50.848 - 25.40 = 25.448 m
hence,
the total displacement = s₁ + s₂ + s₃ = 112 m + 1680 m + 25.448 m
= 1817.448 m