Algebra - Find the acceleration

Question

If an object has an initial speed u m/s and acceleration a m/s² after t seconds, it's final speed (in m/s) is given by the formula v=u+at. Find the acceleration of an object if it's initial speed is 8m/s and it's final speed after 12 seconds is 44m/s.

Answer 1

Hi Bethany!

 

Acceleration is the change in velocity (speed) with respect to time. We are trying to figure out if our object is speeding up or slowing down, and by how much. According to the numbers given, we can see that the object

 

originally travels at 8 m/s <--- this is u

later it travels at 44 m/s <--- this is v, it's bigger than u

 

It is speeding up!

 

the time difference between the measurements is 12 seconds <--- this is t

 

To find out how much, we need to solve for a:

        v = u + at

     v-u = at

(v-u)/t = a

OR

        a = (v-u)/t

 

Great, so now we can put the numbers we've identified as variables into our equation.

Can you solve it from there? Let me know if you still need help.

 

Check: Positive values for acceleration indicate the object is speeding up, if you get a negative number, it's slowing down.