Finding the Tension in a String Using Newton's Laws

In summary, the problem involves Newton's laws and finding the angle theta and tension in the string. The angle theta is found using the acceleration of the van and the downhill force, and the tension is determined by using the equation F=ma and drawing a force diagram. However, despite these efforts, the equation does not seem to work and further guidance or a different approach may be needed.
  • #1
AznBoi
471
0
This problem involves Newton's laws. I got the first half of the problem but I am stuck on the second part. Please take your time to guide me through it, thanks!
Problem:
A van accelerates down a hill, going from rest to 30 m/s in 6 seconds. During the accceleration, a toy (m=.1kg) hangs by a string from the van's ceiling. The acceleration is such that the string remains perpendicular to the ceiling and to the ramp.

Determine a) the angle theta and b) the tension in the string.


Ok I found the angle theta by finding the acceleration of the van with the equation V=Vo+at. Next I found the downhill Force which is .5Newtons. Then I used F sub d(downhill force)=W sin theta. I came up with theta equals 30.677 degrees which is correct because I checked the answer.

How do I find the tension in the string? I tried using F=ma and came up with: F sub d + F sub y + (-T) = ma But that didn't work.. Fy is downward force perpendicular to the ramp, when I got x and y components.


Give me a hint for B) please! Thanks.
 
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  • #2
the only thing that i can recommend is to draw a force diagram and label all the numbers on that and see if you can figure out some sort of equation from that
 
  • #3
yeah I did.. but that's the equation I got and it doesn't work. :frown:
 

FAQ: Finding the Tension in a String Using Newton's Laws

1. What are Newton's Laws of Motion?

Newton's Laws of Motion are three fundamental principles that describe the behavior of objects in motion. They were developed by Sir Isaac Newton in the 17th century and are still used today to explain the motion of objects in the physical world.

2. What is the first law of motion?

The first law of motion, also known as the law of inertia, states that an object at rest will remain at rest and an object in motion will continue in motion with a constant velocity unless acted upon by an external force.

3. What is the second law of motion?

The second law of motion states that the acceleration of an object is directly proportional to the net force acting on the object and inversely proportional to its mass. In simpler terms, the greater the force applied to an object, the greater its acceleration will be. Similarly, the more mass an object has, the less it will accelerate under the same force.

4. What is the third law of motion?

The third law of motion, also known as the law of action and reaction, states that for every action, there is an equal and opposite reaction. This means that when one object exerts a force on another object, the second object will exert an equal and opposite force back on the first object.

5. How are Newton's Laws applied in real life?

Newton's Laws of Motion are applied in many aspects of our daily lives. For example, the first law explains why we need seatbelts in a moving car - because without them, our bodies would continue moving forward at a constant velocity even if the car suddenly stopped. The second law is used in sports, as athletes use force to accelerate their bodies and objects. The third law is seen in action-reaction pairs, such as when a rocket propels itself forward by pushing exhaust gases out in the opposite direction.

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