Question

1. How long will a bus take to travel 150 km at an average speed of

40 km/h?

2.

2. A cheetah can run at 30 m/s, but only for about 12 s. How far

will it run in that time?

3. It takes a cheetah just 3 s to reach its top speed of 30 m/s.

What is its acceleration?

Answer 1

Solution.

$1. l=150km;$

$v=40km/h;$

$l=vt\implies t=\dfrac{l}{v}=\dfrac{150km}{40km/h}=3.75h.$

$2. v=30 m/s;$

$t=12s;$

$l=vt=30 m/s\sdot12s=360m;$

$3. v=30m/s;$

$v_0=0m/s;$

$t=3s;$

$a=\dfrac{v-v_0}{t}=\dfrac{30m/s}{3s}=10m/s^2;$

Answer: $1. l=3.75h;$

$2.l=360m;$

$3. a=10 m/s^2.$