Respuesta :
Answer:
The the speed of the car is 26.91 m/s.
Explanation:
Given that,
distance d = 88 m
Kinetic friction = 0.42
We need to calculate the the speed of the car
Using the work-energy principle
work done = change in kinetic energy
[tex]W=\Delta K.E[/tex]
[tex]\mu\ mg\times d=\dfrac{1}{2}mv^2[/tex]
[tex]v^2=2\mu g d[/tex]
Put the value into the formula
[tex]v=\sqrt{2\times0.42\times9.8\times88}[/tex]
[tex]v=26.91\ m/s[/tex]
Hence, The the speed of the car is 26.91 m/s.
Answer:27 m/s
Explanation:
Given
car's skid length is 88 m long
coefficient of kinetic friction is 0.42
let the mass of car be m and v be the velocity with which it was running initially.
Friction force [tex]=\mu mg=0.42\times m\times g[/tex]
work done by friction force =change in the kinetic energy of car
work done by Friction [tex]=\mu mg\cdot L=\mu mg \times 88cos(180)[/tex]
Change in the Kinetic Energy [tex]=0-\frac{1}{2}mv^2[/tex]
[tex]\mu mg \times 88cos(180)=0-\frac{1}{2}mv^2[/tex]
[tex]0.42\times m\times g=\frac{1}{2}m(v)^2[/tex]
[tex]v=\sqrt{2\times 0.42\times 9.81\times 88}=\sqrt{725.155}=26.92 \approx 27 m/s[/tex]
Mass of car does not matter because in the final expression m gets cancelled.
