Question

Determine the acceleration (in m/s2) of an object which ... . 1. moves in a straight line with a constant speed of 20.0 m/s for 12.0 seconds 2. changes its velocity from 12.1 m/s to 23.5 m/s in 7.81 seconds 3. changes its velocity from 0.0 mi/hr to 60.0 mi/hr in 4.20 seconds 4. accelerates from 33.4 m/s to 18.9 m/s over a distance of 109 m

Answer 1

1) 0 m/s²

2) 1.5 m/s²

3) 6.38 m/s²

4) -3.47 m/s²

Step-by-step explanation:

The acceleration is given by:

`a=(vf-vo)/(t)`

1)

For the first question, the acceleration is zero, because there is no change on its velocity:

`a=((20m/s-20m/s))/(12)=0`

2)

`a=((23.5m/s-12.1m/s))/(7.81)=1.5m/s^2`

3) here we have to make an conversion:

`vo=0m/s\\vf=60.0(mi)/(h)*(1m)/(0.000621mi)*(1h)/(3600s)=26.8m/s`

`a=((26.8m/s-0m/s))/(4.20)=6.38m/s^2`

4) here we have to use the following formula:

`vf^2=vo^2+2*a*x\\\\a=(vf^2-vo^2)/(2*x)\\a=((18.9)^2-(33.4)^2)/(2*(109))=-3.47m/s^2`