Question

A motorist drives North for 30 min at 85 Km/h and then stops for 15 min. He continues travelling North and covers 130 km in 2 hours. What is his total displacement and average velocity?

Answer 1

Hii buddy,

# Answer-
total displacement = 172.5 km
average velocity = 62.73 km/h

# Explanation-
In first 30 min,
t=0.5hr
v=85km/hr
s=0.5×85=42.5km

In next 15 min,
t=0.25hr
v=0
s=0km

In next 2 hrs,
t=2hr
s=130km

Total displacement,
s=42.5+0+130
s=172.5 km

Total time,
t=0.5+0.25+2
t=2.75hrs

Average velocity,
v=s/t
v=172.5/2.75
v=62.73km/hr


Hope that helps you...

Answer 2

Given :

velocity =v1=85 kmph

time=t1=30 min =30/60 hr

Displacement= s1=?

Velocity= v1= displacement / time

S1= velocity x time

=85 x30 /60  

=42.5 km

Displacement covered=s2=130km

t2=15min

t3= 2hours

A) Total displacement = s1+s2

=42.5 + 130 = 172.50 km

B) Average velocity = total Displacement / total time

=s1+s2 / t1+t2+t3

=172.50/(30/60)+(15/60 )+ 2

=172.5 x 60/165

=62.7 km/hr

∴ Average velocity = 62.7 km/hr