A speedboat is travelling along a straight channel. Over a displacement of 42 m, its velocity changes from 4.0 m/s to 10 m/s. The acceleration is uniform throughout this motion.
Use both of these equations in your calculation.
a=v−ut\displaystyle a=\frac{v-u}{t}a=tv−u
v2−u2=2axv^2-u^2=2axv2−u2=2ax
What time does the speedboat take to travel the 42 m?
6.0 s6.0\ \mathrm{s}6.0 s
7.0 s7.0\ \mathrm{s}7.0 s
10.5 s10.5\ \mathrm{s}10.5 s
4.2 s4.2\ \mathrm{s}4.2 s