32.2 (lbf-ft/s^2) is equivalent to how many slugs?

32.2 (lbf-ft/s^2) is equivalent to how many slugs?

• A. 0.5 slug
• B. 2 slugs
• C. 1 slug
• D. 0.1 slug

Answer: (C)

In English engineering units, mass is measured in slugs and force in pounds-force, linked by F = m a. The slug is defined so that a mass of 1 slug accelerated at Earth's gravity (about 32.2 ft/s^2) requires a force of 32.2 pounds-force. So when m = 1 slug and a = 32.2 ft/s^2, F = m a = 32.2 lbf. In this system, slug*ft/s^2 corresponds to lbf, making 32.2 (lbf-ft/s^2) numerically equal to 1 slug. Therefore the equivalent mass is 1 slug. If you change the mass, the force scales linearly (e.g., 0.5 slug would require about 16.1 lbf, 2 slugs about 64.4 lbf).

In English engineering units, mass is measured in slugs and force in pounds-force, linked by F = m a. The slug is defined so that a mass of 1 slug accelerated at Earth's gravity (about 32.2 ft/s^2) requires a force of 32.2 pounds-force. So when m = 1 slug and a = 32.2 ft/s^2, F = m a = 32.2 lbf. In this system, slug*ft/s^2 corresponds to lbf, making 32.2 (lbf-ft/s^2) numerically equal to 1 slug. Therefore the equivalent mass is 1 slug. If you change the mass, the force scales linearly (e.g., 0.5 slug would require about 16.1 lbf, 2 slugs about 64.4 lbf).