Consider the following statements about acceleration: 1. It is a measure of the distance covered per unit time. 2. If an object is in uniform motion, its acceleration is zero. 3. Acceleration can be in the direction of motion or against it. Which of the statements given above are correct?

Correct Option The correct option is (c) 2 and 3 only. Explanation Acceleration is a vector quantity defined as the rate of change of velocity with respect to time. It describes how quickly the velocity of an object is changing in terms of magnitude or direction. Statement-wise Analysis - Statement 1 is Incorrect. Acceleration is the measure of the change in velocity per unit time. The measure of distance covered per unit time is defined as speed. - Statement 2 is Correct. An object is in uniform motion when it moves with a constant velocity (constant speed in a fixed direction). Since there is no change in velocity over time, the acceleration is zero. - Statement 3 is Correct. Acceleration can act in the direction of motion (resulting in an increase in speed) or against the direction of motion (resulting in a decrease in speed). When acceleration acts opposite to the direction of velocity, it is often termed retardation or deceleration. Key Takeaway Acceleration is strictly the rate of change of velocity, not distance. In uniform motion, velocity is constant, meaning acceleration is zero. It is a vector quantity that can oppose motion (retardation).

Consider the following statements about acceleration: 1. It… - NCERT Class 9 Science MCQ

NCERT Class 9 Science — Chapter 1: Motion

mcqmedium

Consider the following statements about acceleration:

It is a measure of the distance covered per unit time.
If an object is in uniform motion, its acceleration is zero.
Acceleration can be in the direction of motion or against it.

Which of the statements given above are correct?

NCERT textbook question

From NCERT Science - class 9 · Page 6

Options

A1 and 2 only
B2 only
C2 and 3 only
D1, 2 and 3

Did you get this right?

Solution

Correct Option

The correct option is (c) 2 and 3 only.

Explanation

Acceleration is a vector quantity defined as the rate of change of velocity with respect to time. It describes how quickly the velocity of an object is changing in terms of magnitude or direction.

Statement-wise Analysis

Statement 1 is Incorrect. Acceleration is the measure of the change in velocity per unit time. The measure of distance covered per unit time is defined as speed.
Statement 2 is Correct. An object is in uniform motion when it moves with a constant velocity (constant speed in a fixed direction). Since there is no change in velocity over time, the acceleration is zero.
Statement 3 is Correct. Acceleration can act in the direction of motion (resulting in an increase in speed) or against the direction of motion (resulting in a decrease in speed). When acceleration acts opposite to the direction of velocity, it is often termed retardation or deceleration.

Key Takeaway

Acceleration is strictly the rate of change of velocity, not distance. In uniform motion, velocity is constant, meaning acceleration is zero. It is a vector quantity that can oppose motion (retardation).

Your note

More from Chapter 1: Motion

An object is said to be in 'uniform motion' along a straight line if:

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The orbital motion of the Moon around the Earth is an example of accelerated motion primarily because:

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If a stone undergoing uniform circular motion is suddenly released, what is the direction of its subsequent trajectory?

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In an automobile, the device known as an 'odometer' is used to measure:

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The phenomenon where roadside trees appear to move backward to a passenger in a moving bus is an example of:

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