**Motion Worksheet-10**

- A student draws a distance-time graph for a moving scooter and finds that a section of the graph is a horizontal line parallel to time axis. Which of the following conclusion is correct about this section of the graph ?

A. The scooter has uniform speed in this section

B. The distance traveled by scooter is the maximum in this section

C. The distance traveled by the scooter is the minimum in this section

D. The distance travelled by scooter is zero in this section.

- Which one of the following is most likely not a case of uniform circular motion ?

A. Motion of the earth around the sun

B. Motion of a toy train on a circular track

C. Motion of a racing car on a circular track

D. Motion of hours’ hand on the dial of a clock

- Study the speed-time graph of a body given here and answer the following question :

What type of motion is represented by OA ?

A. uniform acceleration B. uniform speed

C. uniform retardation D. None of these

- Study the speed-time graph of a body given here and answer the following question :

what type of motion is represented by AB ?

A. uniform acceleration B. uniform speed

C. uniform retardation D. None of these

- Study the speed-time graph of a body given here and answer the following question :

what type of motion is represented by BC ?

A. uniform acceleration B. uniform speed

C. uniform retardation D. None of these

- Study the speed-time graph of a body given here and answer the following questions:

Find out the acceleration of the body.

A. 1.5 m/s^{2} B. –1.5 m/s^{2} C. 0 m/s^{2} D. 2 m/s^{2}

**Answer:**

- D

- C

- A

**Explanation: **OA is a straight line graph between speed and time, and it is sloping upwards from O to A therefore, the graph line OA represents uniform acceleration.

- B

**Explanation: **AB is a straight line which is parallel to the time axis (x-axis). So, AB represents uniform speed (or constant speed). There is no acceleration from A to B.

- C

**Explanation: **BC is a straight line which is sloping downwards from B to C. Therefore, BC represents uniform retardation (or negative acceleration).

- A

**Explanation: **We have just seen that the graph line OA represents acceleration.

So, the slope of speed-time graph OA will give us the acceleration of the body.

Thus

Acceleration = slope of line OA = (AD/OD)

Now, in the given graph, we find that AD = 6 m/s and OD = 4 seconds. So, putting these values in the above relation, we get :

Acceleration = = 1.5 m/s^{2}