High-speed motion pictures (3500 frames/second) of a jumping, 210–μg flea yielded the data used to plot the graph in Fig. E2.54. (See 'The Flying Leap of the Flea' by M. Rothschild, Y. Schlein, K. Parker, C. Neville, and S. Sternberg in the November 1973 Scientific American.) This flea was about 2 mm long and jumped at a nearly vertical takeoff angle. Use the graph to answer these questions: (a) Is the acceleration of the flea ever zero? If so, when? Justify your answer.

Question

High-speed motion pictures (3500 frames/second) of a jumping, 210–μg flea yielded the data used to plot the graph in Fig. E2.54. (See 'The Flying Leap of the Flea' by M. Rothschild, Y. Schlein, K. Parker, C. Neville, and S. Sternberg in the November 1973 Scientific American.) This flea was about 2 mm long and jumped at a nearly vertical takeoff angle. Use the graph to answer these questions: (a) Is the acceleration of the flea ever zero? If so, when? Justify your answer.

Velocity-time graph showing a flea's jump, with velocity in m/s and time in ms.

Speed-time graph illustrating the acceleration of a flea's jump, with speed in cm/s and time in ms.

Accepted Answer

Hey everyone welcome back in this problem. We're using high speed motion pictures to analyze projectile launch from a toy gun. Okay. We're told it's launched at near vertical angle It's 20 g and five cm long. And we get the graph below generated by using the motion pictures And from the graph we want to find when is the acceleration of the projectile zero. Alright, so we're asked about acceleration and let's see here our graph, we have velocity versus time. Yes, we have a velocity time graph. Okay. And so when we're thinking about the relationship between acceleration and a V. T graph, we know that the acceleration okay, is going to be equal to the slope of the curve on our V. T. Graph. Alright, so we're looking for an acceleration of zero. We know that on our on our graph the acceleration is the slope of the curve. Okay, if we want acceleration equals to zero, this means that we want a slope Equal to zero on our graph. Okay, well a slope Equals to zero means that we have a horizontal wine. So let's look at our graph. Where do we see a horizontal line? We see a horizontal line here. Okay, where the slope is zero. So our acceleration is zero. And if we draw down to see what time that is at, we see that this starts at 100 and 50 milliseconds. Okay, so starting at T equals 100 and 50 milliseconds and going onward we are going to have a horizontal line which means the slope of zero, which means an acceleration of zero. Okay, So we're gonna go with Answer B when T is bigger or equal to 150 milliseconds. Alright, that's it for this problem. I hope this video helped see you in the next one.

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