Day Two-A Review Sheets Name______

Concept 8: Graphs of d vs t, v vs t, and a vs t can be used to describe an object’s motion

  1. Tell a story for each picture below.

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  1. What does a p vs t graph showing an upward curve tell us about the motion of an object?______
  2. John is talking on his cell phone and it takes him three times longer than typical to react. He is moving at 10 m/sec.
  3. How long will he travel this time before he can react?______
  4. How far will he travel?______
  5. If I triple my speed, what happens to my reaction time?______
  6. If I triple my speed, what happens to my reaction time distance?______
  7. If I triple my speed, what happens to my braking distance?______
  8. A car, moving at 5 mph, takes 2 feet to stop. How far does it take a car to sop moving at
  9. 10 mph?______
  10. 15 mph?______
  11. 20mph?______
  12. When it is raining, a car moving at 20mph might take 64 feet to stop. How far would this car moving at 10mph take to stop?______

Forces

F = ma, known as Newton’s second law. F = Force, m = mass, a = acceleration

F = ma F/m =aF/a = m

  1. In the metric system,
  2. Mass is measured in ______
  3. Force is measured in ______(pounds in the English system)
  4. Acceleration is measured in meters / second2
  1. What is a typical way to describe a force? A ______or a ______
  1. If I double the force acting on an object, what happens to its acceleration?______
  2. If I cut the mass of an object in half but leave the force constant, what happens to the acceleration?______
  3. If I double the mass of something and leave the force constant, what happens to its acceleration?______
  4. If the acceleration of drag racer declines, what must be happening to the net force on it?______
  5. If the drag racer engine is still putting out the same force, why is the net force declining?______
  6. If I plot Force (y-axis) versus mass (x-axis), what is the slope?______
  7. Brianna is pushing a 10kg cart up a hill. Steven puts an additional 10kg mass in the cart. How much harder does Brianna have to push?______
  1. What is the force on a 1kg object accelerating at 10m/sec2? ______
  1. A 25Newton force is acting on a 10kg mass.
  2. What is its acceleration?______
  3. What happen to its velocity while the force is acting on it?______
  4. What happens to its velocity when the force stops acting on it (in the absence of friction)?______
  5. A 50 Newton force is accelerating an object at 5m/sec2. What is the mass of the object?______

Concept 7: A falling object experiences acceleration due to ______.

  1. Which falls faster in a vacuum – a heavy object or a light object? ______
  2. Which does gravity pull harder on – a heavy object or a light object?______
  3. Which object has more inertia (mass) – a heavy object or a light object?______
  4. What is the ratio of the Force of gravity to the inertia (mass) of the object?______

What might slow an object down if it were not in a vacuum?______

Concept 8: Centripetal Force Fc = mv2/r Fc is the centripetal force, m is the mass, v is the speed orvelocity, r is the distance from the center or the radius

  1. What is centripetal force?______
  1. Name three things that can act as a centripetal force:
  2. ______
  3. ______
  4. ______
  5. If I have a mass of 10 kg and I am going at 10 m/sec in a circle of radius 10m, what is the centripetal force acting on me?______
  6. If I am going in a circle due to a centripetal force and the force disappears, which way will I go?______
  1. If I speed up, what happens to the centripetal force acting on me?______

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  1. If my mass increases, what happens to the centripetal force acting on me?______
  2. If I am driving a car at the same speed, is the centripetal force I need to stay on the road greater or less if I go into a tight curve? (That is, if I reduce the radius of the curve?)______
  3. If I am on a merry-go-round, where do I want to sit to experience the least Fc?___

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  1. What property of matter is a centripetal force interfering with to make me go in a circle?______
  1. Remember our experiments with objects moving in a circle. Which way will the object go?

A BCD