Wonderful! The 2nd EOM says that \(s = u*t + \frac{1}{2}*a*t^2\). We know that \(u = 0, \, t = 5\) and \(a = -10\). We can thus find \(s\).

You are walking on the road. You start from rest and achieve a speed of \(20 \, \mathrm{m/s}\) in \(4 \, \mathrm{s}\). Which of the following would you use to determine your acceleration?

1st EOM: \(v = u + a*t\). 3rd EOM: \(v^2 = u^2 + 2*a*s\)

1st EOM: \(v = u + a*t\). 3rd EOM: \(v^2 = u^2 + 2*a*s\)

1st EOM with \(u = 0 \,\mathrm{m/s}\), \(v = 20 \,\mathrm{m/s} \) and \(t = 4 \, \mathrm{s}\)

2nd EOM with \(u = 0 \mathrm{m/s}\), \(t = 4 \, \mathrm{s}\) and \(a = 10 \mathrm{m/s^2}\)

3rd EOM with \(u = 0 \, \mathrm{m/s}\), \(t = 4 \, \mathrm{s}\) and \(v = 20 \, \mathrm{m/s}\)

1st EOM with \(v = 0 \, \mathrm{m/s}\), \(u = 20 \, \mathrm{m/s}\) and \(t = 4 \, \mathrm{s}\)