OCR M1 2012 January — Question 3

Exam BoardOCR
ModuleM1 (Mechanics 1)
Year2012
SessionJanuary
TopicNon-constant acceleration

3 A car is travelling along a straight horizontal road with velocity \(32.5 \mathrm {~ms} ^ { - 1 }\). The driver applies the brakes and the car decelerates at \(( 8 - 0.6 t ) \mathrm { ms } ^ { - 2 }\), where \(t \mathrm {~s}\) is the time which has elapsed since the brakes were first applied.
  1. Show that, while the car is decelerating, its velocity is \(\left( 32.5 - 8 t + 0.3 t ^ { 2 } \right) \mathrm { m } \mathrm { s } ^ { - 1 }\).
  2. Find the time taken to bring the car to rest.
  3. Show that the distance travelled while the car is decelerating is 75 m .