Practicing Success
The distance travelled by a motor car in t seconds after the brakes are applied is s feet, where $s=22 t-12 t^2$. The distance travelled by the car before it stops, is |
10.08 ft 10 ft 11 ft 11.5 ft |
10.08 ft |
We have, $s=22 t-12 t^2 \Rightarrow \frac{d s}{d t}=22-24 t$ When the car stops, $\frac{d s}{d t}=0$ ∴ $22-24 t=0 \Rightarrow t=\frac{11}{22}$ ∴ $s=22 t-12 t^2 \Rightarrow s=22 \times \frac{11}{22}-12 \times\left(\frac{11}{22}\right)^2$ = 10.08 ft |