Question

A car of mass $1000\,kg$ is moving with a velocity of $10\dfrac{m}{s}$ if the velocity time graph for this car is a horizontal line parallel to the time axis then velocity of the car at the end of $25\sec$ will be ?

Answer 1

A velocity-time graph helps us in finding the speed and direction an object travels over a specific period of time. Velocity-time graphs are also called speed-time graphs. The vertical axis of a velocity-time graph represents the velocity of the object. The horizontal axis represents the time from the starting.

Complete step by step answer:
To solve this question first we need to understand the concept of velocity-time graph. Whenever an object moves with a uniform velocity, then the line on the graph is horizontal in nature. When the horizontal line is present at zero velocity, then this means that the object is in a state of rest. Also, whenever an object is moving with a constant acceleration, the line on the graph is straight but it is sloped.

Whenever we see curved lines on velocity-time graphs, then it means that the velocity is changing, but not with a constant acceleration or deceleration. The steeper the line, the greater is the acceleration of the object. The purple line is steeper than the green line because it represents an object with a greater acceleration.

A line which is sloping downwards with a negative gradient, represents an object moving with a constant deceleration.Since it is mentioned in the question that a horizontal straight line is parallel to the time axis in the velocity-time graph, this means that the velocity is constant. Thus, the velocity of the car at the end of $25\sec$ will be the same, i.e, $10\dfrac{m}{s}$.

Note: Acceleration is calculated by dividing the change in velocity (measured in metres per second) by the time taken for the change to take place (in seconds). The SI unit of acceleration is $\dfrac{m}{{{s^2}}}$. Also, acceleration is a vector quantity, i.e., it has both magnitude as well as direction.