<span>For a point mass the moment of inertia is just
the mass times the square of perpendicular distance to the rotation axis, I =
mr^2. That point mass relationship becomes the basis for all other moments of
inertia since any object can be built up from a collection of point masses. So the
I = (1.2 kg)(0.66m/2)^2 = 0.1307 kg m2</span>
Think of it like this, gravity has to pull harder on the heavier object to make them fall at the same rate , but doesn't have to pull as hard for the lighter object , thus is why sometimes heavier objects fall faster then lighter ones
F = net force acting on the elevator in upward direction = 3000 N
m = mass of the elevator = 1200 kg
a = acceleration of the elevator = ?
Acceleration of the elevator is given as
a = F/m
a = 3000/1200
a = 2.5 m/s²
v₀ = initial velocity of the elevator = 0 m/s
Y = displacement of the elevator = 15 m
t = time taken
Using the kinematics equation
Y = v₀ t + (0.5) a t²
15 = (0) t + (0.5) (2.5) t²
t = 3.5 sec
