Review. A force platform is a tool used to analyze the performance of athletes by measuring the vertical force the athlete exerts on the ground as a function of time. Starting from rest, a 65.0-kg athlete jumps down onto the platform from a height of 0.600 m. While she is in contact with the platform during the time interval 0< t < 0.800 s, the force she exerts on it is described by the function F = 9 200t – 11 500 t 2 where F is in newtons and t is in seconds. (a) What impulse did the athlete receive from the platform? (b) With what speed did she reach the platform? (c) With what speed did she leave it? (d) To what height did she jump upon leaving the platform?
Review. A force platform is a tool used to analyze the performance of athletes by measuring the vertical force the athlete exerts on the ground as a function of time. Starting from rest, a 65.0-kg athlete jumps down onto the platform from a height of 0.600 m. While she is in contact with the platform during the time interval 0< t < 0.800 s, the force she exerts on it is described by the function F = 9 200t – 11 500 t 2 where F is in newtons and t is in seconds. (a) What impulse did the athlete receive from the platform? (b) With what speed did she reach the platform? (c) With what speed did she leave it? (d) To what height did she jump upon leaving the platform?
Solution Summary: The author explains that the impulse received from the platform to the athlete is 981.33Ncdot s.
Review. A force platform is a tool used to analyze the performance of athletes by measuring the vertical force the athlete exerts on the ground as a function of time. Starting from rest, a 65.0-kg athlete jumps down onto the platform from a height of 0.600 m. While she is in contact with the platform during the time interval 0<t< 0.800 s, the force she exerts on it is described by the function
F = 9 200t – 11 500 t2
where F is in newtons and t is in seconds. (a) What impulse did the athlete receive from the platform? (b) With what speed did she reach the platform? (c) With what speed did she leave it? (d) To what height did she jump upon leaving the platform?
A student (m = 58 kg) falls freely from rest and strikes the ground. During the collision with the ground, he comes to rest in a time of
0.04 s. The average force exerted on him by the ground is +18000 N, where the upward direction is taken to be the positive direction.
From what height did the student fall? Assume that the only force acting on him during the collision is that due to the ground.
H=
A worker pushes a 35.0-kg package on a horizontal roller-belt conveyor until it reaches a certain speed. The package then coasts on the horizontal conveyor, all the while slowing down, until it
comes to a complete stop after moving 1.20 m. While the package is coasting on the conveyor, the opposing friction force averages 6.00 N. Use the WET to find the speed of the package
after the worker pushes it and just as it begins to coast.
0.625 m/s
0.759 m/s
0.600 m/s
0.510 m/s
0.802 m/s
0.641 m/s
Whether or not an object (such as a plate, glass, or bone) breaks upon impact depends on the average force exerted on that object by the surface. When a 1.2-kg glass figure hits the floor, it will break if it experiences an average force of 330 N. When it hits a tile floor, the glass comes to a stop in 0.015 s. From what minimum height must the glass fall to experience sufficient force to break? How would your answer change if the figure were falling to a padded or carpeted surface? Explain.
Chapter 9 Solutions
Physics for Scientists and Engineers, Technology Update (No access codes included)
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.