alexislopez792
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 A car whose initial speed is 30 m/s slows uniformly to 10 m/s in 5 seconds. Determine the acceleration of the car. Sketch a graph to support your answer. CHALLENGE: Determine the distance it travels in the 3 seconds.

This one is a little harder because you have to make a graph :(

Respuesta :

  • Initial velocity=u=30m/s
  • Final velocity=v=10m/s
  • Time=5s

[tex]\\ \sf\longmapsto Acceleration=\dfrac{v-u}{t}[/tex]

[tex]\\ \sf\longmapsto Acceleration=\dfrac{10-30}{5}[/tex]

[tex]\\ \sf\longmapsto Acceleration=\dfrac{-20}{5}[/tex]

[tex]\\ \sf\longmapsto Acceleration=-4m/s^2[/tex]

Now

For the second question

  • Time=3s

Using 2nd equation of motion

[tex]\\ \sf\longmapsto s=ut+\dfrac{1}{2}at^2[/tex]

[tex]\\ \sf\longmapsto s=30(3)+\dfrac{1}{2}(-4)(3)^2[/tex]

[tex]\\ \sf\longmapsto s=90-2(9)[/tex]

[tex]\\ \sf\longmapsto s=90-18[/tex]

[tex]\\ \sf\longmapsto s=72m[/tex]

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