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#### The ball left Sharlene's hands at a height of 85 cm above the floor and returns in 0.72s. What was the ball's average speed during the dribble? What was the ball's average velocity during the dribble?

20 viewed last edited 1 year ago
Anonymous
0
So far, I drew the diagram that shows the reference point of where the ball is going. But I am not sure if I drew it right.
What I need help with is how to find out the variables that were not said and if I use the linear motion equation.
Mahesh Godavarti
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I would ask you to consider the following questions. Do you really have to draw a diagram? Do you really have to consider linear motion equations? Remember the definition of average speed = Distance traveled / Total time taken How much distance did the ball travel? In how much time? Remember the definition of average velocity = Displacement / Total time taken What was the change in ball's position? What was the ball's final position with respect to the initial position?
Krishna
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\text{Average Speed} = \frac{Total distance}{time}. Velocity = \frac{displacement}{time}. But distance is a scalar. Displacement is the vector Distance, I think he means the total distance traveled... not the magnitude of the displacement. Given that: The ball left Sharlene's hands at a height (distance) D = 85 cm Time t = 0.72s. What was the ball's average speed during the dribble? What was the ball's average velocity during the dribble? Average Speed = \frac{Total distance}{time}. Average Speed = \frac{85 cm}{0.72s}. Average Speed = 118.0555\frac{cm}{sec}. Average Velocity = \frac{displacement}{time}. Average Speed = \frac{85 cm}{0.72s}. Average Speed = 118.0555\frac{cm}{sec} \text{ down (direction)}.
Mahesh Godavarti
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Hi Krishna, please note that the ball leaves Sharlene's hand AND returns in 0.72s. This is key. You are assuming that it takes the ball 0.72s to leave Sharlene's hand and travel to the ground.