a) You are sitting at the center of the back seat of a car without seat belts and friction is low. The car suddenly makses a right turn. Describe what happens to you. WHich of Newton's laws is applicable?
The car would be goind straight before the turn so when it suddenly turns you also turn with the car. At first you were accelerating forward. Newton's first law be applicable here or is it the second law? Also is my think also correct?
b) A mass sits on a table and the table sits on the Eart. List all foreces acting on the mass, and state whcih forces are third law forces.
1. earth pulling the mass, 2. mass pulling the Earth, 3. table pushing mass 4. mass pushing table 5. normal force from table and 6. gravitational force on mass. The first 4 forces would be third law forces since they involve two different masses.
Is this right?
a) Your thinking is flawed. Intially you are NOT accelerating. When the car starts turning right, you body tends to keep going forward at constant speed relative to the ground below, becasue of Newton's FIRST law. Relative to the car, your mody shifts to the left.
b) All forces are "third law" forces since they have equal and opposite forces opposing them, but only one of the pair act ON the mass. Those would be your #1 (or 6) and #3. Your #6 is the same thing as #1.
a) No, your thinking is not correct. When the car suddenly turns right, according to Newton's first law of motion, also known as the law of inertia, your body tends to continue moving in a straight line at a constant velocity. However, since there is no seat belt to restrain you, there is a lack of friction between you and the car seat. As a result, you will slide towards the left side of the car due to the inertia of your body. This sliding motion is not due to acceleration, but rather your body's resistance to changing its state of motion.
b) Your list of forces is mostly correct, but the identification of "third law forces" needs some clarification. The forces you mentioned can be categorized as follows:
1. Gravity: The gravitational force pulling the mass downwards is exerted by the Earth on the mass. This is not a third law force since it is not acting on two different masses; it is solely acting on the mass.
2. Normal force: The table exerts an upward force on the mass to support its weight. This is not a third law force either, as it is also acting solely on the mass.
3. Table pushing the mass: This is a third law force pair. The mass pushes down on the table, and in response, the table pushes up on the mass with an equal and opposite force.
So, out of your listed forces, only the table pushing the mass and the mass pushing the table (forces 3 and 4 in your list) are third law forces. The gravitational force (force 6) is not considered a third law force in this context.