Name: Activity #73 Choosing a Safe Vehicle Quiz Act # s 73-81 Study Guide 1.) List 4 features of a car that can affect safety by reducing damage, injuries or deaths during car accidents. Air bags, brakes, braking distance, mass, length, width, height, etc Activity #74-Measuring Speed 1.) What is the definition of speed? The distance and object covers in a certain amount of time 2.) What is the formula for speed? Speed=Distance/time 3.) According to your data, how does the release height affect the speed of the cart? Use a complete sentence and provide specific data from act#74. Based on the data from activity#74, the lower the release point, the less speed. Our speed went from 95 cm/s to 55cm/s as we lowered the height 4.) What are the three types of speed? Please list and define each. (Page 9 might be helpful) Type of speed Definition #1 Instantaneous The speed at any single moment in time #2 Constant #3 Average Speed that does not change and remains the same The total distance traveled divided by the total time it took. 5.) What type of speed listed above best represented activity #74, when we measured the distance manually and timed it? Average Speed 6.) What type of speed listed above best represented activity #74, when we used the spark unit? Instantaneous Speed Activity #75-Interpreting Motion Graphs 1.) Why is a motion graph useful? It shows the speed and direction during all parts of the trip 2.) What does the slope of a line in a motion graph tell us? The speed 3.) True/False and EXPLAIN. A downward slope back toward the origin always represents an object slowing down. False, this just means the object is headed back toward the origin or starting point.
The graph to the right represents a typical Sunday afternoon when Mr. Strelick s front door gets opened. The three animals all run out the door and go different speeds and directions. 4.) Who was traveling at the fastest speed and how could you tell? Milo, because he is the coolest! (or because his line has the steepest slope) 5.) Who came back home and how could you tell? Serafina because she is daddy s favorite (or because the line was pointed down) 6.) What was Serafina s speed the first 5 second of her trip? Hint- distance/time. 1 m/s 7.) Which one was accelerating and how could you tell? The mouse, because the line was curved indicating there was not a constant speed and that there was a change in speed Activity #76 & 77-Speed and Collisions/Mass and Collisions 1.) What is the definition of a force? A push or pull that changes an objects motion 2.) How did you quantify the force in these activities? We measured how far the block moved 3.) Two bunnies collide with an large egg. Which one collided with the egg with more force? And why A 10 kg bunny traveling at a speed of 100cm/second A 8 kg bunny traveling at a speed of 6000cm/minute WHY- They are both moving at the same speed, thus the more massive one must have the greater force Activity #78-Force, Acceleration, and Mass 1.) You will need to go back and look at previous activities as well as page 29 to complete the following table Term Definition Unit Force Push or pull that changes an objects motion Newton Mass The amount of matter in an object kg Acceleration The change in velocity over time m/s 2 Velocity The distance and time an object travels in a certain direction m/s
2.) What is the equation for force? Force= Mass Acceleration (F= M A) 3.) What is the equation for acceleration? Acceleration= Change in velocity/time 4.) What is the difference between velocity and speed? (page29) Speed tells you how fast something is moving, while velocity tells you how fast something is moving and in what direction Activity #79-Inertia Around a Curve 1.) Define Inertia without using the terms resistance, laziness or motion. This means you have to use your own words!!!! Object like to keep doing what they are already doing. 2.) What cat has more inertia and explain. Serefina, who weighs 10 pounds and is running at a speed of 5 m/s or Milo, who weighs 13 pounds and is sleeping on the kitchen counter. (yes he does do this) Milo because he has more mass and thus more resistance to change 3.) What is required to get an object to either stop moving, or start moving (change its motion)? A force 4.) What did the circular track apply to the ball to change its motion and keep it in a circular path? A force 5.) Why did the ball go straight out of the circular track when it reached the opening? Why did it not continue in a circle? It no longer had the force of the track pushing it in, so it followed its inertia and went in a straight line. Activity #80-Newton s Laws of Motion 1.) An object at rest will remain at rest unless acted on by an outside unbalanced force 2.) An object in motion will stay in motion with the same speed and in the same direction unless acted on by an outside force 3.) True or False- EXPLAIN- a force is required to keep an object in motion. False, an object in motion will stay in motion 4.) True or False- EXPLAIN The lighter the object, the more force needed to stop it. False, the lighter the object, the less inertia, therefore the less resistance to a change in motion (stopping) 5.) Newton s Third Law says that all forces act in Pairs
6.) For every action force, there is an equal and opposite reaction force 7.) Label and describe the action force and reaction forces in the picture below Action Force- Ball applying a force to the pin Reaction Force Pin applying a force back to the ball 8.) In the example above why does the pin move backward and the ball continues to move forward if both are experiencing equal forces? The pin has much less mass 9.) If a rocket applies a force of 90,000 Newtons on the ground, roughly what force does the ground apply back on the rocket since the rocket is moving and the ground is not? 90,000 Newtons Activity #81-The Net Force Challenge 1.) If a car is parked and not moving, then the forces acting on the car must be a.) balanced b.) unbalanced c.) both 2.) If a car is traveling at a constant speed, then the forces acting on the car must be a.) balanced b.) unbalanced c.) both 3.) If a car is accelerating, then the forces acting on the car must be a.) balanced b.) unbalanced c.) both Use the following information for questions #4-6 Serefina and Milo are both fighting over their favorite cat toy (a stuffed mouse). Milo pulls on the mouse towards the left with a force of 12 Newtons and Serafina pulls on the mouse with a force of 18 Newtons to the right 4.) Draw a force diagram that shows all the forces acting on the mouse. 5.) Draw a Net Force Diagram that only shows the Net Force on the mouse. 6.) How can you tell if the forces acting on an object are balanced or unbalanced? Look to see if the object is accelerating (or changing velocity, or experiencing a change in motion)
Mix-up Math All Activities- Show work for all problems Suggestion- Write what you know first, then determine based on what you are giving and looking for, the equation to use. ***Watch out for the units, in some problems you will need to convert min sec or m cm or vise versa. *** 1.) What is a cars speed if it travels 30m in 1.5 seconds? Speed=? Distance= 30m Time= 1.5 secs Speed= 20 m/s 2.) How long (in hours) would it take to travel 400 miles at a speed of 65MPH Speed= 65 MPH Distance= 400 miles Time=? Time= 6.15 hours 3.) What is the mass of the Lab-Aids cart if its acceleration is 1 m/s 2 and force is 3 Newtons? Force= 3 Newtons Mass= 3 kg Mass=? Acceleration= 1 m/s 2 4.) After an afternoon of chasing his sister around the neighborhood, Milo runs home. The last 2 minutes of his trip he starts to get very tired and goes from 5 m/s to 1 m/s. What is Milo s acceleration the last 2 minutes of his trip? Change in velocity= 5m/s-1m/s=4m/s Time=2mins=120 secs Acceleration=? Acceleration= 0.03 m/s 2 5.) What is the momentum of a football player if they are traveling at a velocity of 9m/s and have a mass of 150kg Momentum=? Mass= 150 kg Velocity= 9 m/s Momentum=Mass velocity Momentum= 150kg 9 m/s Momentum= 1350 kg m/s 6.) What is the force of the above football player when it collides with another player with an acceleration of 12 m/s 2 Force=? Force= mass acceleration Force= 150kg 12 m/s 2 Force= Mass= 150 kg 1800 N Acceleration= 12 m/s 2 7.) What is the acceleration of a 800kg car when hits a wall at a force of 60,000 N Force= 60,000 N Mass= 800 kg Acceleration=? Accel. = 75m/s 2
Random- The following questions relate to multiple activities 1.) Which has more acceleration and explain why. A snake slithering at a constant speed of 2m/s or A giraffe galloping at a speed of 10m/s then slowing to a speed of 4m/s Why- because it is changing speeds which is the definition for an acceleration 2.) Explain how objects on earth do not violate Newton s Law of Inertia? Why don t objects in motion stay in motion on earth? Objects do not stay in motion because they are acted on by the forces of gravity and friction. 3.) If you apply 25 Newtons of force down onto your chair, how many Newtons of force does your chair apply back to you and in what direction? 25 Newtons in the upaward direction 4.) A car is going around a circular track at a constant 15m/s. Is the car experiencing a change in speed? Explain NO, because the speed remains 15m/s Is the car experiencing a change in velocity? Explain Yes, the velocity is changing because the direction is changing. Velocity is speed and direction Is the car experiencing an acceleration? Explain Yes, since it is changing velocity, it must be accelerating. The definition of acceleration is anything that is changing velocity 5.) Something experiencing a BALANCED force is also experiencing a (circle all that apply) a.) An acceleration b.) change in velocity c.) change in motion d.) constant speed 6.) Something experiencing a UNBALANCED force is also experiencing a (circle all that apply) a.) An acceleration b.) change in velocity c.) change in motion d.) constant speed 7.) How does mass differ from weight? Mass is the same no matter what and weight is how much that mass is pulled towards the surface, which depends on gravity 8.) True/false and explain- if an object is moving, it must be experiencing a change in motion? False, an object could be moving at a constant speed which does not represent a change in motion.