The terminal velocity $v_t$ of a skydiver is given by the relationship
$$v_t = \frac{2mg}{\sqrt{\rho AC_d}}$$
where
- $m$ is the mass of the skydiver in kg
- $g$ is the gravitational field strength in N kg$^{-1}$
- $C_d$ is the drag coefficient
- $\rho$ is the density of air in kg m$^{-3}$
- $A$ is the area of the skydiver in m$^2$ - Scottish Highers Physics - Question 7 - 2019
Question 7
The terminal velocity $v_t$ of a skydiver is given by the relationship
$$v_t = \frac{2mg}{\sqrt{\rho AC_d}}$$
where
- $m$ is the mass of the skydiver in kg
- $g$ ... show full transcript
Worked Solution & Example Answer:The terminal velocity $v_t$ of a skydiver is given by the relationship
$$v_t = \frac{2mg}{\sqrt{\rho AC_d}}$$
where
- $m$ is the mass of the skydiver in kg
- $g$ is the gravitational field strength in N kg$^{-1}$
- $C_d$ is the drag coefficient
- $\rho$ is the density of air in kg m$^{-3}$
- $A$ is the area of the skydiver in m$^2$ - Scottish Highers Physics - Question 7 - 2019
Step 1
Calculate the required area of the skydiver:
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Answer
To find the area A, rearrange the terminal velocity equation:
A=ρCdvt22mg
Substituting the values:
m=95 kg
g=9.8 N kg−1
Cd=1.0
ρ=1.21 kg m−3
vt=44 m s−1
This gives:
A=1.21×1.0×(44)22×95×9.8
Calculating this:
Compute the numerator: 2×95×9.8=1864.
Compute the denominator: 1.21×1.0×1936=2343.52.
Now divide: A=2343.521864≈0.796 m2.
Therefore, the closest option is B: 0-79 m2.
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