Question

A car moving at 20
m/s brakes and decelerates uniformly at 8 m/s2. How
much distance does it travel before coming to a stop?

Answer 1

U = 20m/s

V = 0m/s

Deceleration = 8m/s^2

S = ?

From the third equation of motion

${v}^{2} - {u}^{2} = 2as \\ 0 - 400 = 16s \\ s \: = \frac{ - 400}{16} \\ \: = - 25 \: m \:$

As displacement is in opposite direction so it is in negative sign

Therefore, Distance travelled = 25 m

Answer 2

Explanation:

Initial velocity, u = 20 m/s

Acceleration, a= - 8 m/s2

Final velocity, v = 0 m/s

distance travelled , s =

2as=v2-u2

=》s = v2-u2/2a

=》s = 0^2 - 20^2m/s / 2×-8m/s2

=》s = 2.5m

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