Grade 10 Physics: Displacement of Speedboat

[HelloMotto]

Homework Statement

ok here's the question

A speed boat travels at 6.0 m/s [E] for 90s and then accelerates uniformly at 2.0 m/s² [E] for 5.0s. Caculate the displacement of the speedboat

Homework Equations

is this the formula i am suppose to use for this question?

Delta D= V1*Delta T+1/2*A(Delta T)²

note that the a in that formula is suppose to be vector acceleration.

for the time do i just add up 90 seconds and 5 seconds?

 

[PhanthomJay]

Homework Statement

ok here's the question

A speed boat travels at 6.0 m/s [E] for 90s and then accelerates uniformly at 2.0 m/s² [E] for 5.0s. Caculate the displacement of the speedboat

Homework Equations

is this the formula i am suppose to use for this question?

Delta D= V1*Delta T+1/2*A(Delta T)²

note that the a in that formula is suppose to be vector acceleration.

for the time do i just add up 90 seconds and 5 seconds?

No, you should look at the question in 2 parts, the first being the displacement over the first 90 seconds at constant speed (no acceleration), and the second part being the displacement over the next 5 seconds at the given acceleration and initial speed. Then add 'em up. You can't do it all at once, since the acceleartions are different over the noted time periods.