Problem 49
You throw a small rock straight up from the edge of a highway bridge that crosses a river. The rock passes you on its way down, s after it was thrown. What is the speed of the rock just before it reaches the water m below the point where the rock left your hand? Ignore air resistance.
Problem 51a
A rocket starts from rest and moves upward from the surface of the earth. For the first s of its motion, the vertical acceleration of the rocket is given by m/s3, where the -direction is upward. What is the height of the rocket above the surface of the earth at s?
Problem 51b
A rocket starts from rest and moves upward from the surface of the earth. For the first s of its motion, the vertical acceleration of the rocket is given by m/s3, where the -direction is upward. What is the speed of the rocket when it is m above the surface of the earth?
Problem 54a
High-speed motion pictures ( frames/second) of a jumping, flea yielded the data used to plot the graph in Fig. E. (See 'The Flying Leap of the Flea' by M. Rothschild, Y. Schlein, K. Parker, C. Neville, and S. Sternberg in the November Scientific American.) This flea was about mm long and jumped at a nearly vertical takeoff angle. Use the graph to answer this question: Is the acceleration of the flea ever zero? If so, when? Justify your answer.
Problem 54b
High-speed motion pictures ( frames/second) of a jumping, flea yielded the data used to plot the graph in Fig. E. (See 'The Flying Leap of the Flea' by M. Rothschild, Y. Schlein, K. Parker, C. Neville, and S. Sternberg in the November Scientific American.) This flea was about mm long and jumped at a nearly vertical takeoff angle. Use the graph to answer this question: Find the maximum height the flea reached in the first ms.
Problem 54c
High-speed motion pictures ( frames/second) of a jumping, flea yielded the data used to plot the graph in Fig. E. (See 'The Flying Leap of the Flea' by M. Rothschild, Y. Schlein, K. Parker, C. Neville, and S. Sternberg in the November Scientific American.) This flea was about mm long and jumped at a nearly vertical takeoff angle. Use the graph to answer this question: Find the flea's acceleration at ms, ms, and ms.
Problem 62b
A small rocket burns 0.0500 kg of fuel per second, ejecting it as a gas with a velocity relative to the rocket of magnitude 1600 m/s. Would the rocket operate in outer space where there is no atmosphere? If so, how would you steer it? Could you brake it?
Ch 02: Motion Along a Straight Line