Wellington Wildcat is rushing to get to a parade in time to be the grand marshal. He’s standing in the back of a flatbed truck while McFogg the Dog races at 25 m/s towards town. Suddenly, McFogg sees a tiny maple leaf in the road 55 m ahead, and, being a proud Canadian, slams on the brakes to protect the sacred totem. Since McFogg is known to ride the brakes like a real jerk, let’s assume his reaction time to hit the breaks is essentially zero. A. Can McFogg actually stop before the truck reaches the leaf? The coefficients of friction between rubber tires and dry concrete are: μs = 1.00, μk = 0.80. When answering this question, be sure to include a free-body diagram representing the truck and its stellar mascots as a single object. B. Now here’s the real serious question: Is it possible for McFogg to stop short of the leaf such that Wellington does not slip and slide into the back of the truck cab? The coefficients of friction for Wellington’s shoes on the bed of the truck are: μs = 0.60, μk = 0.30. When answering this question, you should include a free-body diagram for the wildcat in peril.
Wellington Wildcat is rushing to get to a parade in time to be the grand marshal. He’s standing in the
back of a flatbed truck while McFogg the Dog races at 25 m/s towards town. Suddenly, McFogg sees a
tiny maple leaf in the road 55 m ahead, and, being a proud Canadian, slams on the brakes to protect the
sacred totem. Since McFogg is known to ride the brakes like a real jerk, let’s assume his reaction time to
hit the breaks is essentially zero.
A. Can McFogg actually stop before the truck reaches the leaf? The coefficients of friction between
rubber tires and dry concrete are: μs = 1.00, μk = 0.80. When answering this question, be sure to
include a free-body diagram representing the truck and its stellar mascots as a single object.
B. Now here’s the real serious question: Is it possible for McFogg to stop short of the leaf such that
Wellington does not slip and slide into the back of the truck cab? The coefficients of friction for
Wellington’s shoes on the bed of the truck are: μs = 0.60, μk = 0.30. When answering this
question, you should include a free-body diagram for the wildcat in peril.
The frictional force is basically resistance to motion. There are two types of frictional force represented in this question, the kinetic frictional force is the force acting between two surfaces that are in motion against each other and static frictional force is the force acting between two surfaces that are attempting to move, but not moving.
So to calculate the deceleration of an object we have to calculate the frictional force. This is done by equating the force equation from Newton's second law to the frictional force.
It can be written as,
Similarly, the static frictional force will be given by,
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