Gravity holds the system together
If I am to understand this question correctly this is what asks you:
If a person is riding a motorized tricycle how much work do they do?
You may ask yourself, why did I only use part of the question. Simple, the rest is not relevant to what is being asked. The weight, speed, and distance wont affect the person riding any <em><u>motorized vehicle</u></em> other than the time it takes to get from one place to another.
So to answer this question I would say:
Not much, all they really have to do is to steer and set the motorized tricycle to cruise control. Just like any rode certified vehicle.
If you have any questions about my answer please let me know and I will be happy to clarify any misunderstandings. Thanks and have a great day!
Answer:
a). 87.5 mA or
A
b). 1.78 
Explanation:

n the number of free electrons is 28 in text reference and if they don't give q is take as the charge of electron.
a).
A
b).


Motion of a ball thrown by a person upwards and caught after some time is an example of motion in which displacement of the particle is zero but acceleration is not zero in journey.
The displacement of the ball is zero because the starting and end point of the motion are same, i.e, the person's hands.During its motion, the acceleration of ball is constant and non zero called as acceleration due to gravity, g= -9.8 m/s². The velocity of ball is continuously changing. It first decreases during the upward motion of the ball and then increases during the downward journey.The acceleration remains constant and non zero all the time.