Failing to identify the start and end point of the motion. The initial point would have set the positive direction for s,v,and a. The convention must be the same for these three vectors , displacement , velocity and acceleration.
Try this!
A hot air ballon is moving vertically upwards at 2ms*-1 when a parcel is dropped out of the carriage. At this instant , the parcel is 35 m from the ground. Calculate the velocity when it hit the ground.Calculate the time taken to hit the ground.
Answer: 26.3 ms*-1 and 2.9 s
