A ball falls from a tall bridge. The ball has a mass of 0.15 kg. The air density is 1.225 kg/m3

. The ball’s surface area is 0.0026 m2
. The ball’s coefficient of drag is 0.007. What is the ball’s terminal velocity?(1 point)
Responses

363 m/s
363 m/s

402 m/s
402 m/s

164 m/s
164 m/s

30.4 m/s

1 answer

To calculate the terminal velocity of the ball, we can use the formula:

\[ V_t = \sqrt{\frac{2mg}{\rho C_d A}} \]

where:

  • \( V_t \) is the terminal velocity,
  • \( m \) is the mass of the object (0.15 kg),
  • \( g \) is the acceleration due to gravity (approximately 9.81 m/s²),
  • \( \rho \) is the density of the fluid (air) (1.225 kg/m³),
  • \( C_d \) is the coefficient of drag (0.007),
  • \( A \) is the cross-sectional area of the object (0.0026 m²).

Now, substituting the values into the formula:

\[ V_t = \sqrt{\frac{2 \times 0.15 , \text{kg} \times 9.81 , \text{m/s}^2}{1.225 , \text{kg/m}^3 \times 0.007 \times 0.0026 , \text{m}^2}} \]

Calculating the values step-by-step:

  1. Calculate the numerator: \[ 2 \times 0.15 \times 9.81 = 2.943 , \text{kg m/s}^2 \]

  2. Calculate the denominator: \[ 1.225 \times 0.007 \times 0.0026 = 0.000022225 , \text{kg/(m s²)} \]

  3. Now plug these into the terminal velocity formula: \[ V_t = \sqrt{\frac{2.943}{0.000022225}} \approx \sqrt{132,434.56} \approx 364.2 , \text{m/s} \]

Rounding, we can say the terminal velocity is approximately \( 363 , \text{m/s} \).

Therefore, the correct choice is:

363 m/s