Test: Motion- Case Based Type Questions- 1 - Class 9 MCQ

This is not possible because it would mean that velocity is increasing without increase in time i.e. acceleration is infinite and infinite acceleration is impossible.

Topic in NCERT: VELOCITY-TIME GRAPHS

Line in NCERT: "Velocity-time graph can never be a straight line parallel to velocity axis."

From B to C, the body uniformly retards as the velocity changes with respect to time.

(b) From A to B, the body has zero acceleration (i.e, retardation) as we know that if the body is uniform velocity acceleration automatically becomes zero here in the graph as we know the body started from 40 metre per second and from A to B, when body reaches at B its velocity remains 40 metre per second.Hence there is no change in velocity and we can say that acceleration is zero in this part of the graph

(c)From B to C, the body has negative acceleration (i.e, retardation) as we know that if the body has some initial velocity u and after sometime t if it gains some velocity v, we can say the body has an acceleration a.if the initial velocity is greater than the final velocity the acceleration becomes negative that is retardation of the body is seen.similarly here at point B if we considered the initial velocity to be 40 metre per second it uniformly retards to 0 m/s by the time it crosses 45 secs.

From A to B, the body has zero acceleration (i.e, retardation) as we know that if the body is uniform velocity acceleration automatically becomes zero here in the graph as we know the body started from 40 metre per second and from A to B, when body reaches at B its velocity remains 40 metre per second.Hence there is no change in velocity and we can say that acceleration is zero in this part of the graph

From B to C, the body has negative acceleration (i.e, retardation) as we know that if the body has some initial velocity u and after sometime t if it gains some velocity v, we can say the body has an acceleration a.if the initial velocity is greater than the final velocity the acceleration becomes negative that is retardation of the body is seen.similarly here at point B if we considered the initial velocity to be 40 metre per second it uniformly retards to 0 m/s by the time it crosses 45 secs.

Topic in NCERT: Uniform and Non-Uniform Motion

Line in NCERT: "Uniform motion from A to B and non-uniform motion from B to C"

From A to B, the body has zero acceleration (i.e, retardation) as we know that if the body is uniform velocity acceleration automatically becomes zero here in the graph as we know the body started from 40 metre per second and from A to B, when body reaches at B its velocity remains 40 metre per second.Hence there is no change in velocity and we can say that acceleration is zero in this part of the graph

(c) From B to C, the body has negative acceleration (i.e, retardation) as we know that if the body has some initial velocity u and after sometime t if it gains some velocity v, we can say the body has an acceleration a.if the initial velocity is greater than the final velocity the acceleration becomes negative that is retardation of the body is seen.similarly here at point B if we considered the initial velocity to be 40 metre per second it uniformly retards to 0 m/s by the time it crosses 45 secs.

Topic in NCERT: Acceleration

Line in NCERT: "the acceleration is taken to be positive if it is in the direction of velocity and negative when it is opposite to the"

The area enclosed by the velocity-time graph and the time axis represents the displacement.

Area enclosed by a velocity-time sketch with time axis represents velocity × time = displacement.

Velocity being a vector quantity, area under time axis corresponds to negative velocity × time = negative displacement.

Topic in NCERT: Velocity-Time Graphs and Displacement

Line in NCERT: "The area enclosed by the velocity-time graph and the time axis will be equal to the magnitude of the displacement."