A man rides in an elevator while standing on a bathroom scale calibrated to read force in Newtons. As the elevator starts to move upwards it speeds up with an acceleration of magnitude 2.1 m/s2. The scale displays a force of 844.9 N. What is the man's mass?

Question

Sheldon Patton

Physics

27 August, 15:52

A man rides in an elevator while standing on a bathroom scale calibrated to read force in Newtons. As the elevator starts to move upwards it speeds up with an acceleration of magnitude 2.1 m/s2. The scale displays a force of 844.9 N. What is the man's mass?

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Answers (1)

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Pierce Hodges · Answer 1

71 Kg

Explanation:

a = 2.1 m/s²

R = 844.9 N

We can apply Newton's Second Law as follows:

R - W = m*a

R - m*g = m*a

m*a + m*g = R

m (a + g) = R

m = R / (a + g)

m = (844.9 N) / (2.1 m/s² + 9.81 m/s²) = 71 Kg