A Parallel circuit has certain characteristics and basic rules: A parallel circuit has two or more paths for current to flow through. Voltage is the same across each component of the parallel circuit. The sum of the currents through each path is equal to the total current that flows from the source.
A motion security line is a system that is used to detect motion.
The input for the system is MOTION and the output is LIGHT. That is, when the system detects motion it switch on light.
Remember, an Input is the information that was inserted into a system while the output is the result of the processed information.
A) use v=u+at for both
First section, v=27, u=0, a=2.4. You should get 11seconds.
Second section, v=0, u=27, a=-1.3. You should get 21seconds.
This means that the total time is 22seconds.
b) You can either use s=ut+0.5at^2 or v^2=u^2+2as. Personally, I would use the second one as you are not relying on your previous answer.
First section, v=27, u=0, a=2.4. You should get 152m.
Second section, v=0, u=27, a=-1.3. You should get 280m.
This makes your overall displacement 432m.
Average Acceleration = (change in speed) / (time for the change)
Change in speed = (ending speed) - (starting speed)
= 15 m/s - 24 m/s = -9 m/s
Acceleration = (-9 m/s) / (12 sec) = - 0.75 m/s² .