Help Understanding Exam Concepts on Forces, Tension & Acceleration

[brownie24]

I am trying to prepare for a exam. It would be great if someone could help me understand these concepts. Thanks!

When rounding a curve in your car, you get the impression
that a force tries to pull you toward the outside
of the curve. Is there such a force?

A fisherman wants to reel in a large dead fish hooked
on a thin fishing line. If he jerks the line, it will break;
but if he reels it in very gradually and smoothly, it will
hold. Explain.

When you are standing on the earth, your feet exert
a push against the surface. Why doesn’t the earth
accelerate away from you?

In a tug–of–war, two teams of children pull on a rope.
Is the tension constant along the entire length of the
rope? Along what portion of the rope is it constant?

When a car accelerates on a level road, the force that
produces the acceleration is the push of the road on
the wheels. If so, why does the automobile need an
engine?

 

[Valerie Park]

Yes, there is a force that tries to pull you toward the outside of the curve, called centrifugal force. This force is caused by the inertia of your body that wants to continue in a straight line and the centripetal force, which is caused by the change in direction that you experience when rounding a curve. The fish will hold if it is reeled in gradually and smoothly because pulling it in too quickly could cause the line to break from the sudden jerk of the force. If the fish is pulled in slowly, it will not cause a sudden pull on the line and the line will be able to support the weight of the fish. The earth does not accelerate away from you because your feet also exert a force on the ground, known as the normal force. This force is equal and opposite to the force that your feet exert and creates an equilibrium. The tension in a tug-of-war rope is constant along its entire length, since the two teams are applying equal and opposite forces along the entire length of the rope. The road pushes against the wheels of the car in order to produce the acceleration, but the engine is necessary to provide the power needed to turn the wheels. The engine is needed in order to transform the energy into motion.

 

[sir-pinski]

Sure, I'd be happy to help you understand these concepts! Let's start with forces. A force is a push or pull on an object that can cause it to accelerate. In the first scenario, when rounding a curve in a car, there is indeed a force that tries to pull you toward the outside of the curve. This force is called centripetal force and it is what keeps an object moving in a circular path. It is directed towards the center of the curve and is necessary to maintain the object's circular motion. Without this force, the object would continue moving in a straight line.

Now, let's talk about tension. Tension is a pulling force that is transmitted through a string, rope, or cable when it is pulled at both ends. In the case of the fisherman reeling in a large fish, the tension in the fishing line is what allows him to gradually and smoothly reel in the fish without breaking the line. This is because the tension acts in all directions along the line, supporting the weight of the fish and preventing it from breaking.

As for the question about standing on the earth and why it doesn't accelerate away from you, this is due to Newton's third law of motion - for every action, there is an equal and opposite reaction. In this case, your feet exert a force on the ground, and the ground exerts an equal and opposite force back on your feet, keeping you in place.

In a tug-of-war, the tension along the rope is constant as long as the rope is not stretching or breaking. This is because the tension is evenly distributed throughout the rope. However, the tension may vary along the rope if there are knots or other obstructions that create points of higher tension.

Finally, the reason why a car needs an engine to accelerate on a level road is because of friction. Friction is the force that opposes motion between two surfaces in contact. In this case, the friction between the tires and the road creates a force that must be overcome by the engine in order for the car to accelerate.

I hope this helps you better understand these concepts and good luck on your exam! Remember to always think about the forces at play in a given situation and how they affect the motion of objects.