Kinematics

 Kinematics and the Coin Toss

 Whiteboard

 Toss the coin into the air and and observe it carefully. Keep in mind the fact that minimum velocity is not the sameas minimum speed, and minimum does not always mean zero. Imagine you toss a coin vertically up in the air such that the coin rises to a maximum height of 2.5m and then returns to your hand. For all following questions, ignore the motion of your hand , and examine the motion of the coin through the air only. Assume the coin leaves your hand and is caught at exactly the same height.

Q1: Sketch the path of this imaginary coin, including a definition of coordinates. Label the following points on your sketch.

 Point 1 The coin has just left your hand moving upwards Point 2 The coin is about 1/4 of the way up to the top of its path Point 3 The coin is about 3/4 of the way up to the top of its path Point 4 The coin is exactly at its maximum height of about 2.5m Point 5 The coin is about 1/4 of the way down from the top of its path Point 6 The coin is about 3/4 of the way down from the top of its path Point 7 The coin is just above your hand and is about to be caught

Q2: Assume upwards displacement is positive. Indicate the following points on your sketches. (In some cases there may be none, or more than one correct point. When this is so, explain in words.)

 Point A Maximum displacement of the coin Point B Zero displacement of the coin Point C Minimum displacement of the coin Point D Maximum velocity of the coin Point E Zero velocity of the coin Point F Minimum velocity of the coin Point G Maximum acceleration of the coin Point H Zero acceleration of the coin Point I Minimum acceleration of the coin

Q3: From your observations in Q2, prepare three sketch graphs: position vs. t, velocity vs. t and acceleration vs. t for one complete toss of the coin. Align the graphs in a colunm so that you can readily read the x,v and a values for the same time.

Q4: In your own words, describe how the position of the coin changes with respect to time during the toss.

Q5: In your own words, describe how the velocity of the coin changes with resect to time during the toss.

Q6: In your own words, desribe how the acceleration of the coin changes with respect to time during the toss.

 References

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