Question

11. Maria left her house bicycling at 10 km/h. Her acceleration was 30 km/h2 . How fast was she bicycling when she arrived at school 30 minutes later?

Answer 1

Answer:

25km/h

Explanation:

we have the information:

initial velocity: $v_{0}=10km/h$

acceleration: $a=30km/h^2$

and the time: $t=30min=0.5h$

the 30 minutes must be in hours because the velocities have hour units.

and now we use the equation for velocity at constant acceleration to now the velocity when she arrived at school 30 minutes (0.5 of hour) later:

$v=v_{0}+at$

and we substitute known values:

$v=10km/h+(30kn/h^2)(0.5h)\\v=10km/h+15km/h\\v=25km/h$

the answer is 25km/h