26 Albert runs faster and faster (accelerates) steadily. Bob is also accelerating but at slower speeds than Albert.Charlie travels:at a constant speed of about 6 m/s for 8 s,stops for 5 s,accelerates for 5 s more.
27 Albert, because he ran the distance in the least time. Who won the race?Albert, because he ran the distance in the least time.
28 Slow, Constant, LeftSlow, Constant, RightFast, Constant, LeftFast, Constant, Right
29 constant velocity in the positive direction (right)
30 constant velocity in the negative direction (left)
32 The blue car starts ahead of the red car (to the left of the screen) The blue car starts ahead of the red car (to the left of the screen). Since the red car is moving faster, it catches up with and passes the blue car.
34 Observe the velocity-time graphs Observe the velocity-time graphs. Each car's motion is represented by a horizontal line (constant velocity).
35 Observe that even though the cars pass each other, the lines on the velocity-time graphs do not intersect. Since the cars never have the same velocity, the lines on the velocity-time graph never cross.
36 The lines would intersect for a position vs The lines would intersect for a position vs. time graph; the red car passing the blue car means that there is an instant when they occupy the same position (at 7 s); yet they never have the same velocity at any instant in time.
37 A velocity-time graph displays speed of an object over time. Plot:velocity on the y-axistime on the x-axis.
38 Positive Velocity,Positive AccelerationPositive Velocity, Zero Acceleration
39 Negative Velocity,Negative AccelerationNegative Velocity, Zero Acceleration
43 Force - a push or pull one body applies to another Force - a push or pull one body applies to another. A force can cause an object’s motion to change.When two or more forces combine at the same time, they create a net force.
44 Balanced forces are equal in size and opposite in direction. Unbalanced forces are unequal in size and/or not in the same direction.