English

Joseph jogs from one end A to the other end B of a straight 300 m road in 2 minutes 30 seconds and then turns around and jogs 100 m back to point C in another 1 minute. What - Science

Advertisements
Advertisements

Question

Joseph jogs from one end A to the other end B of a straight 300 m road in 2 minutes 30 seconds and then turns around and jogs 100 m back to point C in another 1 minute. What are Joseph’s average speeds and velocities in jogging?

  1. from A to B and
  2. from A to C?
Sum
Advertisements

Solution

(a) From A to B.

Time for A to B = 2 min 30s

= 2 × 60 + 30

= 150 s

`"Average speed" = "total distance"/ "time interval"`

= `300/150`

= 2 ms-1

`"Average velocity" = "displacement"/ "time interval"`

= `300/150`

= 2 ms-1

(b) From A to C.

Time taken = A to B + B to C

= 150 + 60

= 210 s

Total distance = 300 + 100

= 400 m

∴ `"Average speed" = "total distace"/"time interval"`

= `400/210 `

= 1.9 m s-1

∴ `"Average velocity" = "displacement"/"time interval"`

= `200/210`

= 0.95 ms-1

shaalaa.com
  Is there an error in this question or solution?
Chapter 8: Motion - Exercises [Page 112]

APPEARS IN

NCERT Science [English] Class 9
Chapter 8 Motion
Exercises | Q 2 | Page 112

Video TutorialsVIEW ALL [1]

RELATED QUESTIONS

Under which condition is the magnitude of average velocity equal to average speed ?


State whether speed is a scalar or a vector quantity. Give reason for your choice.


Arrange the following speed in increasing order (keeping the least speed first): 

An athlete running with a speed of 10 m/s.


A car is moving along a straight road at a steady speed. It travels 150 m in 5 seconds:

How far does it travel in 1 second ?


A train starting from rest moves with a uniform acceleration of 0.2 m/s2 for 5 minutes. Calculate the speed acquired and the distance travelled in this time.


A car is moving on a straight road with uniform acceleration. The speed of the car varies with time as follows :
Time (s)              :     0          2         4          6       8         10
Speed (m/s)       :     4          8       12        16     20         24
Draw the speed-time graph by choosing a convenient scale. From this graph :

(1) Calculate the acceleration of the car.
(2) Calculate the distance travelled by the car in 10 seconds.


A car travels the first 30 km with a uniform speed of 60 km h1 and the next 30 km with a uniform speed of 40 km h1. Calculate :

  1. The total time of journey,
  2. The average speed of the car.

A car accelerates at a rate of 5 m s-2. Find the increase in its velocity in 2 s.


Draw a diagram to show the motion of a body whose speed remains constant, but velocity changes continuously.


Write down the type of motion of a body along with the A – O – B of the following distance – time graph.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×