Which statement best describes the energy changes that occur while a child is riding on a sled down a steep, snow-covered hill?
1 answer:
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Answer:
The velocity of the boat 15 seconds later is 5.6 meters per second.
Explanation:
We assume that sailboat can be modelled as particle, so that we use solely translations equations. It is noticed that the sailboat is move by action of the wind and drag force of the water is opposed to such force, but the last force has a greater magnitude than the first one, meaning that net force is less than zero.
From Newton's Laws we have the following equation of equilibrium for the sailboat:
(Eq. 1)
Where:
- Force from the wind exerted on the sailboat, measured in newtons.
- Drag force of the water, measured in newtons.
- Mass of the sailboat, measured in kilograms.
- Net acceleration of the sailboat, measured in meters per square second.
If we know that ,
and
, then the net acceleration of the sailboat is:
If sailboat decelerates uniformly, then we can get the final velocity of the boat by using this equation of motion:
(Eq. 2)
Where:
,
- Initial and final velocities of the sailboat, measured in meters per second.
- Time, measured in seconds.
If we get that ,
and
, then the final velocity of the sailboat is:
The velocity of the boat 15 seconds later is 5.6 meters per second.