The wheels of a skateboard roll without slipping as it accelerates at 0.40 m/s2 down an 85-m-long hill. Part A If the skateboarder travels at 1.8 m/s at the top of the hill, what is the average angular speed of the 2.6-cm-radius wheels during the entire trip down the hill

Respuesta :

Answer:

average angular speed = 196.92 rad/s

Explanation:

Given data

accelerates down = 0.40 m/s²

down hill travel = 85-m

travels top of hill = 1.8 m/s

radius wheels =  2.6 cm

Solution

We will apply here equation of motion that is express as

[tex]v^{2}-u^{2}[/tex] = 2as    ...............1

here v is final velocity  and u is final velocity  and s is dispalement

so put here value we get first final velocity

[tex]v^{2} = 1.8^{2}[/tex]  + 2 × 0.40 × 85

solve it we get

[tex]v^{2}[/tex]  = 71.24

v = 8.44 m/s

and

initial angular speed is express as

initial angular speed ω = [tex]\frac{u}{r}[/tex] ............2

put here value

initial angular speed ω = [tex]\frac{1.8}{2.6 \times 10^{-2}}[/tex]

initial angular speed ω = 69.23 rad/s  

and

final angular speed ω = [tex]\frac{v}{r}[/tex]    ..............3

put here value

final angular speed ω =  [tex]\frac{8.44}{2.6 \times 10^{-2}}[/tex]  

final angular speed ω = 324.61 rad/s  

so now we get  average of angular speed that is

average angular speed = ( 69.23 + 324.61  ) ÷ 2

average angular speed = 196.92 rad/s