Question

A body travels 30 m with speed 10 m s and 40 m with speed 15 m s . Calculate average speed for entire journey.



pls give me full answer​

Answer 1

t1=30/10=3 seconds

t2= 40/15= 2.7 seconds

average speed= total distance/Total time taken

= 70/5.7= 12.28

or

you can use the formula

2v1v2÷v1+v2

2×10×15÷10+15

300÷25=12 is the right answer

this formula came from

let distance be x

and you know the speeds

t1=x/v1

t2=x/v2

average speed = x+x/x/v1+x/v2

2x/x(v1+v2/v1v2)

2v1v2/v1+v2 as x got cancelled

Answer 2

Answer:

• 12.34 m/s

Explanation:

As per the information provided in the question, We have :

• A body travels 30 m with speed 10 m/s and 40 m with speed 15 m/s.

We are asked to find average speed of entire journey.

In order to find the avg. speed, we will need find total distance travelled are total time taken.

Total distance :

$\longmapsto \rm Total \: distance = 30 + 40$

Performing addition in RHS.

$\longmapsto \rm Total \: distance = 70 \: m$

∴ The total distance traveled is 70 m.

Total time taken :

Time is given by –

$\longmapsto \bf Total \: time = \dfrac{Distance _{(Total)} }{Speed _{(Total)} }$

Putting the given values,

$\longmapsto \rm Total \: time = \dfrac{30 }{10} + \dfrac{40}{ 15}$

$\longmapsto \rm Total \: time = 3 + 2.67$

$\longmapsto \rm Total \: time = 5.67 \: {m/s}$

∴ Total time taken is 5.67 m/s.

Average speed :

$\longmapsto \bf Speed_{(Avg)}= \dfrac{Distance _{(Total)} }{Time _{(Total)} }$

Putting the value we have,

$\longmapsto \rm Speed _{(Avg)}= \dfrac{70}{5.67}$

$\longmapsto \rm Speed _{(Avg)}= 12.34 \: m / {s}$

∴ Hence, Average speed of the body is 12.34 m/s.