A motorist drives north for 35.0 minutes at 85.0 km/h and then stops for 15.0 minutes he next continues north traveling 130 km in 2.00hours What is his total displacement
Answers
Explanation:
Since it's travelling in the same direction for the entire duration of its journey, the total displacement of the car is simply the distance from the starting point.
In the first part of its journey, the car travelled for 35 minutes at a speed of 85 km/h. Convert the time from minutes to hours to get
35
min
⋅
1 h
60
min
=
0.5833 h
This means that the car covered
0.5833
h
⋅
85 km
1
h
=
49.6 km
The car stops, then continues along its current direction, covering 130 km in 2 hours. The total displacement of the car will thus be
d
total
=
49.6
+
130
=
179.6 km
The average velocity is simply the total dispalcement divided by the total time of travel. In your case, the total time will be
t
total
=
0.5833 h
+
0.25 h
= 15 min
+
2 h
=
2.833 h
The average velocity is
¯
v
=
179.6 km
2.833 h
=
63.4 km/h