Q1. Describe Newton's 1st Law.

Background

Topic: Newton's Laws of Motion

This question tests your understanding of Newton's First Law, also known as the law of inertia, which describes the behavior of objects when no net force acts upon them.

Key Terms:

• Inertia: The tendency of an object to resist changes in its state of motion.

• Net Force: The vector sum of all forces acting on an object.

Step-by-Step Guidance

1. Recall that Newton's First Law states what happens to an object when the net external force is zero.

2. Think about the two possible states of motion: at rest and moving with constant velocity.

3. Consider how this law explains why objects keep doing what they're doing unless acted on by an unbalanced force.

Try explaining the law in your own words before checking the answer!

Q2. Describe Newton's 2nd Law.

Background

Topic: Newton's Laws of Motion

This question tests your understanding of how force, mass, and acceleration are related.

Key Formula:

• = net force (in Newtons, N)

• = mass (in kilograms, kg)

• = acceleration (in meters per second squared, m/s^2)

Step-by-Step Guidance

1. Recall that Newton's Second Law quantifies the effect of force on an object's motion.

2. Think about how the acceleration of an object depends on both the net force applied and the object's mass.

3. Consider how this law is used to solve problems involving forces and motion.

Try stating the law and its mathematical form before checking the answer!

Q3. Describe Newton's 3rd Law.

Background

Topic: Newton's Laws of Motion

This question tests your understanding of action-reaction force pairs.

Key Terms:

• Action Force: The force one object exerts on a second object.

• Reaction Force: The force the second object exerts back on the first.

Step-by-Step Guidance

1. Recall that Newton's Third Law deals with forces between two interacting objects.

2. Think about the direction and magnitude of these forces.

3. Consider examples, such as pushing against a wall or two ice skaters pushing off each other.

Try to state the law in your own words before checking the answer!

Q4. Block 1 collides with block 2. The force block 1 exerts on block 2 is related to the force that block 2 exerts on block 1 in what way?

Background

Topic: Newton's Third Law (Action-Reaction Pairs)

This question tests your understanding of how forces between two objects interact during a collision.

Key Concept:

• Action-reaction force pairs are always equal in magnitude and opposite in direction.

Step-by-Step Guidance

1. Identify the two objects involved in the interaction (block 1 and block 2).

2. Recall Newton's Third Law and how it applies to collisions.

3. Think about the direction and magnitude of the forces each block exerts on the other during the collision.

Try to describe the relationship before checking the answer!

Q5. You are on a high-speed train, and you have a drink resting on a table. The conductor of the train makes an abrupt stop, and the drink slides off the table. Why did the drink slide off the table?

Background

Topic: Inertia (Newton's First Law)

This question tests your understanding of how inertia affects objects when the frame of reference changes suddenly.

Key Terms:

• Inertia: The tendency of an object to resist changes in its motion.

• Reference Frame: The perspective from which motion is observed and measured.

Step-by-Step Guidance

1. Consider what happens to the train and the drink when the train stops abruptly.

2. Recall Newton's First Law and how it applies to the drink's motion.

3. Think about whether any force acted directly on the drink to stop it, or if it continued moving due to inertia.

Try to explain the reason before checking the answer!

Q6. Draw a free body diagram for a block sliding down an incline with and without friction. Find an expression for the acceleration of the block in terms of the angle of the incline, coefficient of kinetic friction, and g for both cases.

Background

Topic: Forces on Inclined Planes, Friction

This question tests your ability to analyze forces acting on an object on an incline, both with and without friction, and to derive the acceleration in each case.

Key Formulas:

• Gravitational force component along the incline:

• Normal force:

• Kinetic friction force:

• Newton's Second Law:

Step-by-Step Guidance

1. Draw the free body diagram for the block on the incline, showing gravity, normal force, and (if present) friction.

2. Resolve the gravitational force into components parallel and perpendicular to the incline.

3. For the frictionless case, set up Newton's Second Law along the incline: .

4. For the case with friction, include the kinetic friction force: .

5. Express in terms of and , and substitute .

Try to write the final acceleration expressions for both cases before checking the answer!

Q7. If you are holding a mass of 100 grams attached to a spring scale and you raise it at constant velocity what force does the scale read? What force would the scale read if you accelerate it upwards at 1 m/s^2? Accelerate it downwards at 1 m/s^2? (Hint: A spring scale reads the Tension force in the object it is holding up.)

Background

Topic: Forces, Tension, Apparent Weight

This question tests your understanding of how tension in a spring scale changes depending on the acceleration of the mass.

Key Formulas:

• Newton's Second Law:

• Forces acting: Tension () upward, Weight () downward

• For upward acceleration:

• For downward acceleration:

Step-by-Step Guidance

1. Convert the mass to kilograms: .

2. For constant velocity, set acceleration and solve for .

3. For upward acceleration, use in .

4. For downward acceleration, use in .

Try calculating the tension for each case before checking the answer!

Q8. Explain the difference between weight, apparent weight, and mass.

Background

Topic: Mass, Weight, Apparent Weight

This question tests your understanding of the differences between these three related but distinct concepts.

Key Terms:

• Mass (): The amount of matter in an object (measured in kg).

• Weight (): The gravitational force on an object, .

• Apparent Weight: The normal force or the force a scale reads, which can differ from true weight if the object is accelerating.

Step-by-Step Guidance

1. Define mass and explain why it is constant regardless of location or acceleration.

2. Define weight and explain how it depends on the local gravitational acceleration .

3. Define apparent weight and describe situations where it differs from true weight (e.g., in an elevator or accelerating system).

Try to write your own definitions before checking the answer!

Q9. Convert 10 mph to meters per second.

Background

Topic: Unit Conversion

This question tests your ability to convert between different units of speed.

Key Conversion Factors:

Step-by-Step Guidance

1. Write the speed as .

2. Convert miles to meters: .

3. Convert hours to seconds: .

4. Set up the conversion: .

Try calculating the value before checking the answer!

Q10. At a radius of 10 cm the speed of an object in circular motion is 1 m/s. What is the angular speed in rad/s?

Background

Topic: Circular Motion, Angular Speed

This question tests your understanding of the relationship between linear speed and angular speed.

Key Formula:

• = linear (tangential) speed (m/s)

• = radius (m)

• = angular speed (rad/s)

Step-by-Step Guidance

1. Convert the radius to meters: .

2. Write the formula relating linear speed and angular speed: .

3. Rearrange to solve for : .

4. Plug in the values: m/s, m.

Try calculating before checking the answer!