Acceleration MCQs Quiz | Class 9
Class IX Science (Code 086), Unit III: Motion, Force and Work. This quiz covers the topic of Acceleration, focusing on its definition, units (m/s squared), and concepts of uniformly accelerated motion. Test your knowledge, check your score, and download the answer key PDF for revision.
Understanding Acceleration
Acceleration is a fundamental concept in physics describing how the velocity of an object changes over time. It is a vector quantity, meaning it has both magnitude and direction.
In simple terms, if an object speeds up, slows down, or changes direction, it is accelerating. The standard formula for acceleration (a) is defined as the change in velocity (v – u) divided by the time taken (t).
Key Concepts & Units
| Concept | Description |
|---|---|
| Definition | Rate of change of velocity with time. |
| SI Unit | Meter per second squared (m/s squared). |
| Formula | a = (v – u) / t |
| Uniform Acceleration | Velocity changes by equal amounts in equal time intervals. |
| Retardation | Negative acceleration (velocity decreases). |
Equations of Motion
For an object moving with uniform acceleration along a straight line, three equations relate initial velocity (u), final velocity (v), acceleration (a), time (t), and displacement (s):
- First Equation: v = u + at
- Second Equation: s = ut + (1/2)at squared
- Third Equation: 2as = v squared – u squared
Practice Questions for Revision
- A bus decreases its speed from 80 km/h to 60 km/h in 5 seconds. Calculate the acceleration.
- A train starting from a railway station and moving with uniform acceleration attains a speed of 40 km/h in 10 minutes. Find its acceleration.
- What is the nature of the distance-time graph for non-uniform motion?
- Under what condition is the magnitude of average velocity equal to average speed?
- If a car starts from rest, what is its initial velocity? (Answer: 0 m/s)
