Question

1. A car of mass 100 kg is moving with a velocity of 10m/sec. If the
velocity time graph for this car is a horizontalline parallel to time axis,
then the velocity of a car at end of 25 sec will be (MARK-1)
a. 40m/sec
b. 10ms?
c. 250ms
d. 25ms 1​

Answer 1

Provided that:

• Mass of car = 100 kg
• Velocity = 10 m/s
• Time = 25 seconds

Solution:

• Velocity = 10 m/s

To determine: If the velocity- time graph for this car is a horizontal line parallel to the time axis the velocity of car at the end of 25 sec will be

Knowledge required:

→ If the slope of the velocity time graph is parallel to the time axis then the velocity is constant at any time.

Solution:

~ As the slope of the velocity time graph is parallel to the time axis then the velocity is constant at any time and here also the velocity- time graph for this car is a horizontal line parallel to the time axis. Therefore, the velocity of car at the end of 25 sec will be 10 m/s.

Therefore, option (b) is correct! $\:$

Additional information:

Distance = It is the length of actual path covered by a moving object in a given time interval.

Displacement = Shortest distance covered by a body in a definite direction is called displacement.

→ Displacement may be positive, negative or zero whereas distance is always positive.

→ Distance is a scaler quantity whereas displacement is a vector quantity both having the same unit.

→ In general magnitude of displacement ≤ Distance.

Speed = Distance travelled by a moving object in unit time interval is called speed i.e., speed Distance/Time. It's scaler quantity and it's SI unit is metre/second

Velocity = Velocity of moving object is defined as the displacement of the object in unit time interval i.e., velocity = Displacement/Time. It's vector quantity and it's SI unit is metre/second.

Acceleration = Acceleration of an object is defined as the rate of change of velocity of the object i.e., Acceleration = Change in velocity/Time. It's vector quantity and SI unit is m/s²