# Midterm Review Essays

Midterm Review Name: ______________________________ Date: ___________ Circle Period R1 R2 R3 S1 S2 S3 Chapter 1 – About Science Vocabulary: Define each term. Fact: Hypothesis: Law: Theory: Check Concepts: 1. Why is physics the most basic science? 2. Why is mathematics important to science? 3. Is a scientific fact something that is absolute and unchanging? Defend your answer. Chapter 2 – Mechanical Equilibrium Vocabulary: Define each term. Force: Net Force: Vector: Vector Quantity: Scalar Quantity: Mechanical Equilibrium: Equilibrium Rule: Support Force: Resultant: Check Concepts: 1.

What is the difference between force and net force on an object? 2. What is the net force on a box that is being pulled to the right with a force of 40 N and pulled to the left with a force of 30 N? 3. What two quantities are necessary to determine a vector quantity? 4. How does a vector quantity differ from a scalar quantity? 5. Distinguish between static equilibrium and dynamic equilibrium. 6. According to the parallelogram rule for two vectors, what does the diagonal of a constructed parallelogram represent? 7. Why doesn’t the support force that acts on a book resting on a table cause the book to rise from the table? . The sketch shows a painter’s staging in mechanical equilibrium. The person in the middle weighs 250 N, and the tensions in both ropes are 200 N. What is the weight of the staging? 9. A staging that weighs 300 N supports two painters, one 250 N and the other 300 N. The reading in the left scale is 400 N. What is the reading in the right scale? 10. Two children push on a heavy crate that rests on a basement floor. One pushes horizontally with a force of 150 N and the other pushes in the same direction with a force of 180 N. The crate remains stationary.

Show that the force of friction between the crate and the floor is 330 N. Chapter 3 – Newton’s First Law of Motion - Interia Vocabulary: Define each term. friction : inertia : Newton’s first law: law of inertia: kilograms: mass: newton: Check Concepts 1. What were the two classifications of motion, according to Aristotle? 2. According to Aristotle, what kinds of motion required no forces? 3. What simple way of interpreting astronomical observations did Copernicus advocate? 4. Who relied on experiment, Aristotle or Galileo? 5.

How did Galileo discredit Aristotle’s assertion that a force is needed to keep objects moving? 6. Galileo let a ball roll down one incline and then up another. Compared with its initial height, how high did the ball roll up the second incline? 7. What is the tendency of an object at rest when no forces act on it? 8. What is the tendency of a moving object when no forces act on it? 9. What relationship does mass have with inertia? Think and Rank… 10. The three pucks are sliding across ice at the noted speeds. Air resistance and ice friction are negligible. a.

Rank them, from greatest to least, by the force needed to keep them going. b. Rank them, from greatest to least, by the force needed to stop them in the same time interval. 11. To pull a wagon across a lawn with constant velocity, you have to exert a steady force. 12. Does this fact contradict Newton’s first law which tells us that motion with constant velocity indicates no force? 13. When a junked car is crushed into a compact cube, does its mass change? Its volume? Its weight? 14. If an elephant were chasing you, its enormous mass would be very threatening.

But if you zigzagged, the elephant’s mass would be to your advantage. Why? 15. When you compress a sponge, which quantity changes: mass, inertia, volume, or weight? 16. Which has more mass, a 2-kg fluffy pillow or a 3-kg small piece of iron? More volume? Why are your answers different? Chapter 4 – Linear Motion Vocabulary: Define each term. Relative: Speed (define and give equation): Instantaneous Speed: Average Speed (define and give equation): Velocity (define and give equation): Acceleration (define and give equation): Free Fall: Elapsed Time: Check Concepts: 1. You can cover 10 meters in one second.

Is your speed the same if you cover 20 meters in 2 seconds? 2. Does the speedometer of a car read instantaneous speed or average speed? 3. What 2 controls on a car cause a change in speed? What control causes only a change in velocity? 4. What is the acceleration of a car moving along a straight line path that increases its speed from zero to 100 km/h in 10sec? 5. For a freely falling object dropped from rest, what is the acceleration at the end of the filth second of fall? The sixth second? 6. Does air resistance increase or decrease the acceleration of a falling object?

Plug and Chug: 7. Calculate your average walking speed when you step 15 meters in 10 second. 8. Calculate the speed of a baseball that moves 20 meters in 8 seconds. 9. Calculate your average speed if you if you run 25 meters in 5 seconds. 10. Calculate the acceleration of a bus that goes from 20 km/h to a speed of 60 km/h in 10 seconds. 11. Calculate the vertical distance on object dropped from rest would cover in 35 seconds if it fell freely without air resistance. (d = ? gt2) Think and Explain: 12. Correct your friend who says “Speed is a vector quantity. ” 13.

Which has more acceleration when moving in a straight line – a car increasing its speed from 50 to 60 km/h, or a bicycle that goes from zero to 10 km/h in the same time? Defend your answer. 14. A car is traveling 75 km/h west. A second car is traveling 75 km/h south. Are the two cars going the same speed? Are they going the same velocity? Defend your answer. Think and Rank: 15. Jogging Jake runs along a train flatcar that moves at the velocities shown. From greatest to least, rank (A, B, C, D) the relative velocities of Jake as seen by an observer on the ground. Call the direction to the right positive) Chapter 5 – Projectile Motion Vocabulary: Define each term. Components: Projectile: Resolution: Check Concepts: 1. How does a vector quantity differ from a scalar quantity? 2. If a vector that is 1 cm long represents a velocity of 10 km/h, what velocity does a 3. vector 2 cm long drawn to the same scale represent? 4. At the instant a ball is thrown horizontally over a level range, a ball held at the side of the first is released and drops to the ground. If air resistance is neglected, which ball strikes the ground first? 5.

Neglecting air resistance, if you throw a ball straight up with a speed of 20 m/s, how fast will it be moving when you catch it? 6. The airplane is blown off course by wind in the directions shown. Use the parallelogram rule and rank from highest to lowest the resulting speed across the ground. (A, B, C, D) 7. Calculate the resultant velocity of an airplane that normally flies at 200 km/h if it encounters a 50-km/h tailwind. If it encounters a 50-km/h headwind. 8. Calculate the magnitude of the resultant of a pair of 100-km/h velocity vectors that are at right angles to each other. (Remember a2+b2=c2) . Calculate the resulting speed of an airplane with an airspeed of 120 km/h pointing due north when it encounters a wind of 90 km/h directed from the west. (Remember a2+b2=c2) Chapter 6 – Newton’s Second Law of Motion Vocabulary: Define each term. Inversely- Newton’s second law- fluid- air resistance- free-body diagram- pressure- pascal- terminal speed- terminal velocity- Check Concepts: 1. What produces acceleration? 2. Is acceleration directly proportional to mass, or is it inversely proportional to mass? 3. If the net force acting on a sliding block is tripled, what happens to the acceleration? 4.

When do you produce more pressure on the ground, standing or lying down? 5. Each block on the friction-free lab bench is connected by a string and pulled by a second falling block. Rank each from greatest to least. (A, B, C) These questions are to familiarize you with the key equations of the chapter. Acceleration=net force/mass (a=F/m) 6. Calculate the acceleration of a 40-kg crate of softball gear when pulled sideways with a net force of 400 N. 7. Calculate the acceleration of a 2500-kg, single-engine airplane as it begins its takeoff with an engine thrust of 1000 N with an air resistance force of 200N. 8.

Calculate the acceleration of a 300,000-kg jumbo jet just before takeoff when the thrust for each of its four engines is 30,000 N. 9. Calculate the acceleration if you push with a 20-N horizontal force against a 2-kg block on a horizontal friction-free air table. 10. F = ma 11. Calculate the horizontal force that must be applied to a 2-kg puck to make it accelerate on a horizontal friction-free air table with the same acceleration (10m/s2) it would have if it were dropped and fell freely. 12. Calculate the horizontal force that must be applied to produce an acceleration of 20m/s2 for a 2-kg puck on a horizontal friction-free air table. 3. How does the weight of a falling body compare with the air resistance it encounters just before it reaches terminal velocity? Just after it reaches terminal velocity? Chapter 7 – Newton’s Third Law of Motion Vocabulary: Define each term. Interaction: Newton’s third Law: action force: reaction force: Check Concepts: 1. Can an action force exist without a reaction force? 2. When a hammer exerts a force on a nail, how does this amount of force compare with that of the nail on the hammer? 3. When you walk on a floor, what pushes you along? 4.

Consider hitting a baseball with a bat. If we call the force the bat exerts against the ball the action force, identify the reaction force. 5. If a bat hits a ball with 1000 N of force, can the ball exert less than 1000 N of force on the bat? More than 1000 N? 6. If you hit a wall with a force of 200 N, how much force does the wall exert on you? 7. Some people used to think that a rocket could not travel to the moon because it would have no air to push against once it left Earth’s atmosphere. We now know that idea was mistaken. What force propels a rocket when it is in a vacuum? . Since the force that acts on a cannonball when a cannon is fired is equal and opposite to the force that acts on the cannon, does this imply a zero net force and therefore the impossibility of an accelerating cannonball? Explain. Graphing Speed: Create a line graph that shows you are moving 5km/h. Have the graph show your time for 50km. Remember that time is the independent variable and goes on the x-axis. Distance is the dependant variable and goes on the y-axis. Do not forget your labels and title for the graph. Your plotted data show your speed (D/T)