Physics problems with Newton's Law

In summary, the sailboat experiences an eastward force of 27400 N due to tide pushing its hull while the wind pushes the sails with a force of 56200 N directed toward the northwest (45± westward of North or 45± northward ofWest). The resultant acceleration of the sailboat is 3.4 m/s2.
  • #1
bigslowy
3
0
These problems are really giving me fits, I would really appreciate some help.

A 12200 kg sailboat experiences an eastward
force of 27400 N due to tide pushing its hull
while the wind pushes the sails with a force of
56200 N directed toward the northwest (45±
westward of North or 45± northward ofWest).
What is the magnitude of the resultant ac-
celeration of the sailboat?



I'm using Fr= square root of (Frx squared)+(Fry squared) but I'm still not getting it right. I'm thinking that maybe I drew the free body diagram wrong. Any help?

Now for this one

The distance between two telephone poles is
32 m. When a 1:15 kg bird lands on the
telephone wire midway between the poles, the
wire sags 0:182 m.
The acceleration of gravity is 9:8 m=s2 :
How much tension in the wire does the
bird produce? Ignore the weight of the wire.

So far I've drawn the diagram and got a hypotenuse of 16.001 m, but I'm unsure how to finish the problem.

Any help would be much appreciated.
 
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  • #2
1. Find the magnitude using the cosine law.
2. use F=ma to find the magnitude of a.
It is easier to use the unit vector i and j. but i am afraid you haven't learned that yet. so we will approach it geometrically.
 

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  • #3
First problem (sail boat)

check the attachment

Fx = F(east) - F(northwest)Xcos45 = -12339 N
Fy = F(northwest)Xsin45 = 39739 N
Fnet = Squareroot of (Fx^2 + Fy^2)
then, Fnet = ma
a = Fnet/mass = 3.4 m/s
 

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  • #4
2nd problem

ok the hyp that you got is good.
a^2 + b^2 = c^2
a= 16
b = .182
c = 16.001 using the formula. Good you got until this point.

2nd step= get the angle theta. (see diagram)

90-tan (16/.182) = theta


step 3 = Get the tension by adding the Forces on the y axes. See diagram
 

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  • #5
Free body diagram : Attached file.
 

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  • #6
of course, I didn't draw the other tension on the other side because is understood.
 

1. What is Newton's First Law of Motion?

Newton's First Law of Motion, also known as the Law of Inertia, states that an object will remain at rest or in motion with a constant velocity unless acted upon by an external force.

2. How do Newton's Laws of Motion apply to physics problems?

Newton's Laws of Motion are fundamental principles in physics that explain the relationship between forces and motion. They can be used to analyze and solve various types of problems involving motion, such as calculating forces, acceleration, and velocity.

3. What is the difference between mass and weight in Newton's Second Law?

Mass is the measure of an object's inertia, or resistance to change in motion, while weight is a measure of the force of gravity acting on an object. In Newton's Second Law, mass is used to calculate the amount of force needed to accelerate an object, while weight is often used to represent the force of gravity.

4. How can Newton's Third Law be applied to real-world situations?

Newton's Third Law states that for every action, there is an equal and opposite reaction. This can be applied to real-world situations such as walking, where our feet push against the ground and the ground pushes back on our feet, allowing us to move forward. It also explains how rockets are able to launch into space by pushing exhaust gases downward, creating an equal and opposite force that propels the rocket upward.

5. What are some common misconceptions about Newton's Laws of Motion?

One common misconception is that an object must be in motion for Newton's Laws to apply. In reality, they can also be used to analyze objects at rest. Another misconception is that Newton's Laws only apply to large objects, when in fact they apply to all objects regardless of size. Additionally, some may incorrectly believe that the net force on an object must be zero for it to be at rest, when in fact it must have a net force of zero to remain at a constant velocity.

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