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druuuuuuuunnk
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Homework Statement
A mass of 80 kg rests on the floor of a lift. (Take g = 10ms-2). Calculate:
(a) the reaction force exerted on the object by the floor, when the lift is
travelling at a steady speed of 2 ms-1 downwards.
(b) the reactive force exerted on the object by the floor of the lift, as its
downward motion is brought to rest by a retardation of 4ms-2.
(c) the reactive force exerted on the object by the floor, when the lift is at rest.
Gravity = 10 m/s-2
Homework Equations
F=M.A
The Attempt at a Solution
(a) becuase there is a steady speed downwards, do i just use gravity as the accelleration and nothing else? so F= (80) x (10) F=800 N
/or/ is it F= (80) x (10+2) F=960 N
(b) F= (80) x (10-4) so F= 480 N
(c) F= (80) x (10) F=800
My teacher this year has been pretty useless if you could help me understand this i would be really gratful.