A small firecracker is suspended 0.60 m from the ceiling and 3.0 m from the floor in a very large room. The firecracker explodes, and the fragments fly off in all directions with the initial speed of 8.0 m/s. Find the radius of the area on the floor in which the fragments land. The collisions of the fragments with the ceiling are elastic, and the collisions with the floor—inelastic. The acceleration due to gravity is 9.8 m/s2.


The 2019-2020 season of Challenges had a strong finish, with many readers from all over the world submitting their solutions to our March, April, and May problems.

We are pleased to recognize the following contributors:

Syed Abuthahir (Dr. Zakir Husain College, Ilayangudi, Tamil Nadu, India)

Juan M. Aguirregabiria (University of the Basque Country, Bilbao, Spain)

Hubert N. Biezeveld (Zwaag, The Netherlands)

Phil Cahill (The SI Organization, Inc., Rosemont, PA)


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