Question

A car moves at speed of 40 km/hr for 2 hrs then speed of 50 km/hr for next 3 hrs. Find the average speed of the car​

Answer 1

Answer:

a.

260

km

b.

43.3

km

hrs

=

12

m

s

Explanation:

a. In the 1st section, the car goes

40

km

h

r

⋅

2

h

r

s

=

80

km

In the 2nd section, the car goes

50

km

h

r

⋅

3

h

r

s

=

150

km

In the 3rd section, the car goes

30

km

h

r

⋅

1

h

r

s

=

30

km

The sum of those sections is

(

80

+

150

+

30

)

km

=

260

km

b.

Average speed

=

total distance

total time

. Total time in this problem is

6

hrs

, so

Average speed

=

260

k

m

6

hrs

=

43.3

km

hrs

Converting that to units of m/s:

43.3

k

m

h

r

s

⋅

1000

m

1

k

m

⋅

1

h

r

3600

s

=

12

m

s