In the graph, which two regions show the particle undergoing zero acceleration and negative acceleration respectively?

BC shows zero acceleration , and CD shows negative acceleration ⇒ C

Explanation:

Acceleration is the rate of change of velocity

So in the time velocity graph the slope of a line represents the

acceleration because the slope of the line is the change in y (velocity)

for the change of x (time)

If the line has positive slope, then the acceleration is positive

If the line has negative slope, then the acceleration is negative

If the line has zero slope, then the acceleration is zero

A line has positive slope if y increased when x increased

A line has negative slope if y decreased when x increased

A line has zero slope if it is a horizontal line, that means y constant and

x increased

Lets look to the graph

x-axis represents the time in seconds

y-axis represents the velocity in meters per second

→ Line AB:

y increased from 0.5 m/s to 1 m/s

x increased from 0 to 3 seconds

The slope of line AB is positive

Line AB shows positive acceleration

→ Line BC:

Y in the same value 1 m/s

x increased from 3 seconds to 4 seconds

The slope of line BC is zero

Line BC shows zero acceleration

→ Line CD:

y decreased from 1 m/s to 0 m/s

x increased from 4 to 6 seconds

The slope of line AB is negative

Line CD shows negative acceleration

BC shows zero acceleration , and CD shows negative acceleration