12. Slope of a v-t graph is the acceleration and never curves. The area (under the slope) is the displacement.
13. Slope of a d-t graph is the velocity. Curved line = acceleration. The area (under the slope) is the velocity.
14. Area of an a-t graph is the change in velocity.
15. Horizontal line on a d-t graph means that the displacement is currently 0 (no movement). On a v-t graph – it is a constant velocity. On an a-t graph – there is no acceleration (constant velocity).
16. Negative slope on a d-t graph means that it has a constant negative velocity. On a v-t graph, the acceleration is negative.
18. Three ways of acceleration: increasing speed, decreasing speed, and changing direction.
19. Turn a corner with constant acceleration? No, because the velocity changes due to direction. Zero acceleration? No, because the speed would also be zero.
20. Negative velocity and positive acceleration? Yes, with free-falling objects. Positive velocity and negative acceleration? Yes, with projectiles.
21. Acceleration of an object in freefall – 9.8 m/s/s. What are some examples? Baseball, football, etc.
22. Acceleration – Zero in horizontal. -9.8 m/s^2 in vertical. At peak, horizontal is 0, vertical is 0. Just before caught, the acceleration is force of gravity.
28. Terminal Velocity – When force of drag acting on it is equal to force of gravity acting on it. Occurs during free-fall when acceleration equals zero because of air resistance.
46. Friction – The resistive force that keeps an object from moving.
47. Earth moves in a circle because of its and the sun’s gravitational pulls. Otherwise, it would continue towards the sun.
48. Mass vs. weight = Mass is one’s weight in proportion to its gravitational field. To find mass, you must multiply the weight (in kg) x 9.8 (gravity) to get the mass in kg.
49. Benefit corners – Causes the passenger lean closer to you while making a turn. Newton’s Third Law – a force is exerted on an object when that object interacts with another object in its environment.
50. The penny would drop. To an observer, it would fly backwards.
51. Newton’s Second Law – NF = ma, or net force = mass x acceleration. The acceleration of an object is directly proportional to the net force acting on the object and inversely proportional to the object’s mass.
52. Normal Force – A force that is perpendicular to the surface upon which an object moves. NF = -mg. Also, the weight of an object + any vertical forces on the object. Gravity.
53. Tension in each rope is equal to half of the object’s mass.
55. Static Friction – Happens when the force of friction is greater than the applied force; results in no motion.Kinetic Friction – Happens when the object “breaks free” and moves. The force upon the object overcomes the force of friction.
56. Normal force always equals weight? No. The normal force and weight are the same only when there are no forces acting upon it.
57. Because only one object is moving, the horse. The cart’s velocity = 0 until the horse pulls it.
58. There is a greater force on the fly because the flyswatter has a larger mass, but the fly has the greater acceleration. (Eq = F=ma).
59. Newton’s Third Law – If two objects interact, the magnitude of the force exerted on object 1 by object 2 is equal to the magnitude of the force simultaneously exerted on object 2 by object 1, and these two forces are opposite in direction.
70. Conservation of Momentum – Total momentum of two objects before a collision is equal to the momentum of the two objects after collision. Momentum lost by object 1 = momentum gained by object 2.
71. Vectors For Momentum:a. Head on collision (two objects move in opposite directions and collide)
72. b. Back end collision (two objects moving in same direction and then collide)
79. R(center of gravity) = masses * average of their positions / massesEQUATIONS:<br />Torque = FD (Force * Distance or length)<br />Force = T / D<br />Distance = T / F<br />