- #1

annamal

- 381

- 33

- Homework Statement
- A small diamond of mass 10.0 g drops from a swimmer’s earring and falls through the water, reaching a terminal velocity of 2.0 m/s. a) Assuming the frictional force on the diamond obeys what is b? (b) How far does the diamond fall before it reaches 90 percent of its terminal speed?

- Relevant Equations
- v_t = terminal velocity

a) -m*g + b*v = m*a = 0 for terminal velocity

b = m*g/v_t

b) My question is here:

0.9v_t = v0 + a*t = a*t

t = 0.9v_t/a

delta_h = v0*t + 0.5*a*t^2 = 0.5*a*t^2 = 0.5*((0.9*v_t)^2)/a =

where a = (-m*g + b*v)/m

delta_h = (0.5*((0.9*v_t)^2)*m)/(-m*g + b*v)

plugging in everything delta_h = 1.65 m which is not what the answer is. Please help

b) My question is here!

0.9v_t = v0 + a*t = a*t

t = 0.9v_t/a

delta_h = v0*t + 0.5*a*t^2 = 0.5*a*t^2 = 0.5*((0.9*v_t)^2)/a =

where a = (-m*g + b*v)/m

delta_h = (0.5*((0.9*v_t)^2)*m)/(-m*g + b*v)

plugging in everything delta_h = 1.65 m which is not what the answer is. Please help

0.9v_t = v0 + a*t = a*t

t = 0.9v_t/a

delta_h = v0*t + 0.5*a*t^2 = 0.5*a*t^2 = 0.5*((0.9*v_t)^2)/a =

where a = (-m*g + b*v)/m

delta_h = (0.5*((0.9*v_t)^2)*m)/(-m*g + b*v)

plugging in everything delta_h = 1.65 m which is not what the answer is. Please help