Density: A certain coin has a diameter of 21.21 mm, a thickness of 1.95 mm, and weighs 0.04905 N. What is its density? A) 29.1 × 10³ kg/m³ B) 7.26 × 10³ kg/m³ C) 9.25 × 10³ kg/m³ D) 2.31 × 10³ kg/m³ E) 71.2 × 10³ kg/m³

Question

Quizplus · Accepted Answer

First, we need to find the volume of the coin. Using the diameter and thickness given, we can find the volume of the coin using the formula for the volume of a cylinder:

V = πr^2h

where r is the radius (half the diameter) and h is the thickness.

r = 21.21/2 = 10.605 mm = 0.010605 m

h = 1.95 mm = 0.00195 m

V = π(0.010605)^2(0.00195) = 2.08 × 10^-7 m^3

Next, we can find the density of the coin using the formula:

ρ = m/V

where ρ is density and m is mass.

m = 0.04905 N / 9.81 m/s^2 = 0.005 kg

ρ = 0.005 kg / 2.08 × 10^-7 m^3 = 7.26 × 10^4 kg/m^3

Therefore, the answer is B.

Density: a Certain Coin Has a Diameter of 21