question_answer

  The speedometer readings of a car are shown below. Find the acceleration of the car and its displacement. Time Speed do meter 9:25 AM 36 km/h 9:45 AM 72 km/h

Answer:

                \[u=36\text{km/h}=36\times \frac{5}{18}=10\text{m/s}\]                 \[u=72\text{km/h}=72\times \frac{5}{18}=20\text{m/s}\] \[t=6:45-9:25=20\min =20\times 60=1200\text{s}\] \[a=?s=?\] \[a=\frac{\upsilon -u}{t}=\frac{20-10}{1200}=\frac{10}{1200}=\frac{1}{120}\text{m/}{{\text{s}}^{\text{2}}}\] \[s=\frac{{{\upsilon }^{2}}-u}{2a}=\frac{{{(20)}^{2}}-{{(10)}^{2}}}{2\times \frac{1}{120}}=\frac{400-100}{1/60}\] \[=300\times 60=18000\,\text{m}=18\,\text{km}\]