Question

An object moving at 13 m/s slows uniformly at the rate of 2.0m/s each second for
a time of 6 seconds. Determine (a) Its final velocity (b) Its average speed duringthe 6 seconds (c) the distance moved in 6 seconds.

Answer 1

Here a = -2 m/s² and u = 13 m/s t = 6s

We know v = u+at

(a) then v = 13 - 2 x 6 = 1 m/s = Final velocity

(b) Total displacement = $ut+\frac{1}{2}at^{2} = (13\times6)-(\frac{1}{2}\times2\times6^{2}) = 78-36 = 42 m$

      Avg velocity = $\frac{Total\:displacement}{Total\:time} = \frac{42}{6} = 7 m/s$

(c) Distance moved in 6 s = 42 m (Check solution of (b))