Answer:
50
Explanation:
The mechanical advantage of a machine is given by

where
is the output force
is the input force
For the crowbar in this problem,
is the force in input applied by the worker
is the force that the machine must apply in output to overcome the resistance of the window and to open it
Substituting into the equation, we find

Mid-ocean ridges happen along divergent plate boundaries, where new ocean floor is created as the Earth’s tectonic plates spread apart. As the plates separate, molten rock rises to the seafloor, producing large volcanic eruptions of basalt.
Answer:
Large; small.
Explanation:
A telescope can be defined as an optical instrument or device which comprises of a curved mirror and lenses used for viewing distant objects i.e objects that are very far away such as stars and other planetary bodies. The first telescope was invented by Sir Isaac Newton.
To have the highest magnification in a telescope, the focal length of the objective lens should be large and the focal length of the eyepiece lens should be small.
This ultimately implies that, the eyepiece lens has a small focal length while the objective lens has a large focal length.
Answer: 8000N
Explanation: since it is frictionless that means it has 100% efficiency therefore the mechanical advantage is 1 meaning the load equals to the effort
Answer:
The length of chain she is allowed is 1.169 ft
Explanation:
The given parameters are;
The linear density of the chain = 0.83 lb/ft
The weight limit of the chain she wants = 1.4 lb
The formula for linear density = Weight/length
Therefore, in order to keep the chain below 1.4 lb, we have;
Linear density = Weight/length
Therefore;
The maximum length she wants = Weight/(Linear density)
Which gives;
The maximum length she wants = 1.4 lb/(0.83 lb/ft) =1.169 ft
Therefore;
The length of chain she is allowed = 1.169 ft.