A window washer on a hanging platform cleans the outside of windows on a skyscraper. The washer hoists the platform up the side
of the building by pulling down on a rope that runs up over a pulley and then runs back down and connects to the top of the platform. The combined mass of the washer and the platform is 100kg, and the washer pulls on the rope with a force of 800N. What is the acceleration of the platform?
1 answer:
Answer:
Acceleration of the platform = - 1.8 m/s²
Explanation:
The net force acting on a body accelerates the body in the same direction as that in which the resultant is applied.
Writing the force balance for the setup,
ma = 800 - mg
100a = 800 - 100×9.8
100a = - 180
100a = - 180
a = - 1.8 m/s²
This means the body falls downwards.
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here on sled two forces will do work
1. Applied force by Max
2. Frictional force due to ground
Now by force diagram of sled we can see the angle of force and displacement
work done by Max =
Now similarly work done by frictional force
Now total work done on sled
Answer:
About 7.67 m/s.
Explanation:
Mechanical energy is always conserved. Hence:
Where <em>U</em> is potential energy and <em>K</em> is kinetic energy.
Let the bottom of the slide be where potential energy equals zero. As a result, the final potential energy is zero. Additionally, because the child starts from rest, the initial kinetic energy is zero. Thus:
Substitute and solve for final velocity:
In conclusion, the child's speed at the bottom of the slide is about 7.67 m/s.