An object starts at rest then accelerates at a rate of 5m/s^2 for 1 second and then 2m/s^2 for 2 seconds. what is the average acceleration over time (t€[0,3]

Acceleration = (change in speed) / (time for the change)

-- during the first second, the object increases its speed to

(5 m/s²) · (1 s) = 5 m/s .

-- During the next 2 seconds, the object increases its speed by

(2 m/s²) · ( s) = 4 m/s

So at the end of the whole 3 seconds, its speed is (5 m/s) + (4 m/s) = 9 m/s

-- Over the whole time, its speed has changed from zero to 9 m/s.

Acceleration = (change in speed) / (time for the change)

Acceleration = (9 m/s) / (3 sec)

Acceleration = 3 m/s²

diagram is missing, but i will try to explain your doubt.

answer:

amplitude is the maximum displacement or distance moved on a point of a vibrating body or wave measured from its equilibrium position.it is equal to half the length of vibration path.

the answer is to check all of them! they all apply well at least i think so!