You are moving into an apartment and take the elevator to the 6th floor. Suppose your weight is 790 N and that of your belonging
1 answer:
Answer:
a)
b)
Explanation:
Given the information from the exercise we can calculate the work done by the elevator using the following formula:
a) Considering you and your belongings as a system we know that the elevator is applying a Normal reaction force of:
Since the force applied and the displacement is in the same direction, the work done by the elevator is positive
b) The reaction force applied by the elevator is the same as the weight of the person
Since the force applied and the displacement is in opposite direction, the work done by the elevator is negative
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Answer:
Explanation:
Weight of the ladder is 355N
WL = 355N
The weight of the ladder acts at center of the ladder I.e at 4m from the bottom
Weight of firefighters is 870N
Wf = 870N
The fire fighter is at 6.3m from the bottom of the ladder.
N1 is the normal force exerted by the wall
N2 is the normal force exerted by the ground
Using Newton law
Check attachment
ΣFy = 0, since body is in equilibrium
N₂ - WL - Wf = 0
N₂ = WL + Wf
N₂ = 870 + 355
N₂ = 1225 N
This the normal force exerted by the ground on the wall.
Now to get N₁, let take moment about point A
So, before we take the moment we need to make sure that the forces are perpendicular to the plane(ladder), we need to resolve the weight of the ladder, firefighter and the normal of the wall to be perpendicular to the plane.
ΣMa = 0
Clockwise moment is equal to anti-clockwise moment
Moment Is the produce of force and perpendicular distance.
M = F×r
So,
WL•Cos50 × 4 + Wf•Cos50 × 6.3 —N₁•Sin50 × 8 = 0
355•Cos50 × 4 + 870•Cos50 × 6.3 =
N₁•Sin50 × 8
1825.52 + 3523.12 = 6.13N₁
6.13N₁ = 5348.64
N₁ = 5348.64/6.13
N₁ = 872.54 N.
The normal force exerted by the wall is 872.54N
The concepts used to solve this exercise are given through the calculation of distances (from the Moon to the earth and vice versa) as well as the gravitational potential energy.
By definition the gravitational potential energy is given by,
Where,
m = Mass of Moon
G = Gravitational Universal Constant
M = Mass of Ocean
r = Radius
First we calculate the mass through the ratio given by density.
PART A) Gravitational potential energy of the Moon–Pacific Ocean system when the Pacific is facing away from the Moon
Now we define the radius at the most distant point
Then the potential energy at this point would be,
PART B) when Earth has rotated so that the Pacific Ocean faces toward the Moon.
At the nearest point we perform the same as the previous process, we calculate the radius
The we calculate the Potential gravitational energy,