Maria is painting the trim on the top of a building. She drops her paintbrush. The paintbrush has a velocity of 29.4 m/s when it hits the ground 3 s later. What is the acceleration of the paintbrush?

1 Answer
May 26, 2017

Answer:

#a=9.8m/s^2#

Explanation:

Use the formula #a=(v_f-v_i)/(t_f-t_i)# where #a# is the acceleration, #v_f# the final velocity, #v_i# the initial velocity, #deltat# the change in time, which can also be written as #t_f-t_i#.

3 seconds later suggests that the change in time was 3 seconds.

The final velocity is 29.4m/s

The initial velocity is 0 because that was the velocity of the paintbrush just as it started its descent.

Therefore,
#a=(29.4-0)/3#
#a=9.8#

This is the speed of acceleration due to gravity on Earth. Initially, you could've solved it by looking at it but I wanted to give you how to work out answers like this.