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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Answer:
The balloon hit the ground with velocity -15.34 m/s
Explanation:
<em>Lets explain how to solve the problem</em>
You found that the best height to pitch a water balloon in order for it to
burst when it hits the ground is 12 meters.
We consider that the 12 meters is the maximum height, so the velocity
at this height is zero.
To find the velocity when the balloon hits the ground lets use the rule
<em>v² = u² + 2gh</em>, where v is the final velocity, u is the initial velocity, g is
the acceleration of gravity and h is the height.
u = 0 , h = 12 m , g = 9.8 m/s²
<em>Substitute these values in the equation above</em>
v² = 0 + 2(9.8)(12)
v² = 235.2
<em>Take square root for both sides</em>
v = ±
The velocity is downward, then it's a negative value
Then v = -15.34 m/s
<em>The balloon hit the ground with velocity -15.34 m/s</em>