Suzie (of mass 42 kg) is roller-blading down the sidewalk going 32 miles per hour. She notices a group of workers down the walkway who have unexpectedly blocked her path, and she makes a quick stop in 2.2 seconds. a) What is Suzie's average acceleration? Answer in units of m/s 2. b) What force in Newtons was exerted to stop Suzie? Answer in units of N.

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Physics

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10 January, 20:24

Suzie (of mass 42 kg) is roller-blading down the sidewalk going 32 miles per hour. She notices a group of workers down the walkway who have unexpectedly blocked her path, and she makes a quick stop in 2.2 seconds. a) What is Suzie's average acceleration? Answer in units of m/s 2. b) What force in Newtons was exerted to stop Suzie? Answer in units of N.

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Answers (1)

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Tiana Schultz · Answer 1

a) Suzie's average acceleration = - 6.46 m/s²

b) Force exerted to stop Suzie = 271.52 N

Explanation:

a) We have equation of motion, v = u + at

Final velocity, v = 0 m/s

Initial velocity, u = 32 mph = 14.22 m/s

Time, t = 2.2 s

Substituting

0 = 14.22 + a x 2.2

a = - 6.46 m/s²

Suzie's average acceleration = - 6.46 m/s²

b) Mass of Suzie = 42 kg

Force = Mass x Acceleration

F = Ma

F = 42 x - 6.46 = -271.52 N

Force exerted to stop Suzie = 271.52 N