The formula for accelerational displacement is at^2/2, so we know that 3.9t^2/2 = 200, or 3.9t^2 = 400. t = 
, at = v, so 
Sultan throws a ball horizontally from his window, 12 m above the garden. It reaches the ground after
1 answer:
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Answer:
a) The change in potential energy of a 3.0 kilograms backpack carried up the stairs.
b) The change in potential energy of a persona with weight 650 newtons that descends the stairs is -2665 joules.
Explanation:
Let consider the bottom of the first floor in a building as the zero reference (). The change in potential energy experimented by a particle (
), measured in joules, is:
(1)
Where:
- Mass, measured in kilograms.
- Gravitational acceleration, measured in meters per square second.
,
- Initial and final height with respect to zero reference, measured in meters.
Please notice that is the weight of the particle, measured in newtons.
a) If we know that ,
,
and
, then the change in potential energy is:
The change in potential energy of a 3.0 kilograms backpack carried up the stairs.
b) If we know that ,
and
, then the change in potential energy is:
The change in potential energy of a persona with weight 650 newtons that descends the stairs is -2665 joules.