An what is any device that makes work easier
by changing the input force.

A machine

Explanation:

A machine is any device that makes work easier. Machines make work easier by changing the strength or direction of a force. Machines do not decrease the amount of work that needs to be done, they just make work easier by changing the way it is done.

  distance on the y-axis and time on the x-axis.

explanation:

the instantaneous velocity = change in position/time taken

the slope of the graph should give instantaneous velocity.

  slope of a graph = change in value of y -axis / change in values of x -axis

  comparing both the equations

    change in value of y -axis = change in position

  change in values of x -axis = time taken

so position values should be on the y axis and time values should be on the x axis.

distance on the y-axis and time on the x-axis.

it is a negative acceleration