Newton’s Laws Review

Newton's Laws Review

Key Concepts

Newton's Laws of Motion explain the relationship between a body and the forces acting upon it, and the body's motion in response to those forces.

Questions & Answers

Q1: What is the weight of an object?A: Weight is the force exerted on an object due to gravity, usually measured in newtons (N).

Q2: What is the net force when you have 1200 N and 400 N?A: The net force is the vector sum of the forces, which is 800 N.

Q3: What happens to a spinning washer if you let it go?A: It moves in a straight line due to inertia until acted upon by another force.

Q4: What happens to a cue ball's speed when it hits other balls?A: The cue ball decreases speed as momentum is transferred to the other balls.

Q5: How do you find acceleration (a = F/m)?A: Acceleration is found by dividing the net force by the mass of the object; this relates to Newton's 2nd Law.

Q6: What are noncontact forces?A: Noncontact forces act at a distance, such as gravitational, magnetic, and electric forces.

Q7: What happens to an object if there is no net force acting on it?A: According to Newton's 1st Law, the object will maintain its state of motion (either at rest or moving at a constant velocity).

Q8: What is momentum?A: Momentum is the product of an object's mass and its velocity, indicating how difficult it is to stop the object.

Q9: What happens to the momentum of the cue ball when it hits other balls?A: The cue ball loses momentum, which is transferred to the other balls.

Q10: What do we call the forces between two objects?A: These are known as action-reaction force pairs.

Q11: How fast does a 0.5 kg basketball thrown with a 15 N force accelerate?A: It accelerates at 30 m/s² based on Newton's 2nd Law (a = F/m).

Q12: What happens when you push against a wall?A: This demonstrates Newton's 3rd Law: for every action, there is an equal and opposite reaction.

Q13: What is inertia?A: Inertia is the tendency of an object to resist changes in its state of motion.

Q14: What do we call collisions where objects stick together?A: These collisions are called inelastic collisions.

Q15: How does swimming, jumping, and rockets show action-reaction forces?A:Swimming: Push water back (action), water pushes you forward (reaction).Jumping: Push down (action), ground pushes you up (reaction).Rocket: Engine pushes gas down (action), gas pushes rocket up (reaction).

Q16: What happens to objects at rest or moving with no net force?A: This is explained by Newton's 1st Law: they remain at rest or in uniform motion.

Q17: Why do we weigh less in space?A: Because you are farther from the center of the Earth, so gravitational force is weaker.

Q18: How do you define force?A: A force is a push or pull acting upon an object that can cause it to change velocity.

Q19: How do car brakes affect your motion?A: They illustrate Newton's 1st Law: an object in motion will stay in motion unless acted upon by an external force.

Q20: How does the momentum of a golf ball compare to a baseball at the same speed?A: The baseball, being heavier, has greater momentum than the golf ball at the same speed.

Q21: What is centripetal force?A: Centripetal force is directed towards the center of a circular path, keeping an object in uniform circular motion.

Q22: Why does friction occur?A: Friction results from the interactions between the microscopic surfaces of objects in contact.

Q23: What is mass?A: Mass is the amount of matter in an object, typically measured in kilograms (kg).

Q24: What does the Law of Equal and Opposite Forces mean?A: Newton's 3rd Law states that forces act in equal and opposite pairs.

Q25: How is net force calculated?A: Net force is calculated by summing all forces acting on an object, taking into account their directions.

Q26: What happens to gravity when mass increases?A: An increase in mass results in an increase in gravitational force.

Q27: What is needed to move a heavier object?A: More force is required to accelerate a heavier object compared to a lighter one.

Q28: What does the Law of Conservation of Momentum say?A: It states that in a closed system, the total momentum remains constant unless acted on by an external force.

Q29: What is an elastic collision?A: An elastic collision is one in which kinetic energy is conserved; the objects bounce off each other without losing energy.

Q30: What happens to an object at rest if there is no force acting on it?A: It will remain at rest due to inertia.

Q31: How do two golf balls compare in momentum?A: The ball with the higher speed will have greater momentum.

Q32: What is contact force?A: A contact force is a force that occurs when two objects are physically touching each other.

Q33: How are mass and weight related?A: Weight is the gravitational force acting on an object’s mass; more mass means more weight.

Q34: How does friction affect movement?A: Friction opposes motion, causing objects to slow down.

Q35: What happens to mass and weight on the moon?A: Mass remains constant, but weight decreases due to weaker gravity.

Q36: How does distance affect gravitational attraction?A: The closer two objects are, the stronger the gravitational attraction between them.