a) In a recent Tour de France time trial, a participant traveled 30.5 mi in a time trial in 1h,
10min. What was his average sped in mph?
b) What is the speed in Km/h?
SOL:
a) Time (t) = 1h, 10min
10
= 1h + h
60
7
= h
6
distance
Velocity (v) =
time
30.5
v= 7
6
183
v=
7
= 26.143 mph
b) Average speed = (26.143) (1.60934)
= 42.073km/h.
In most countries outside the United States speed is measured in kilometers per hour (Km/h)
rather than miles per hour(mph). Although the exact conversion from km/h to mph is 0.57, a
conversion factor of 0.6 is generally used because it is easier to remember. For the reverse
conversion a factor of 1.7 is normally used. Perform the following conversions using the
approximate conversion factors.
a) What is the speed in mph of an automobile on the German Autobahn travelling at 160
km/h?
b) What s the speed in km/h of motorcycle travelling at 70mph in the United States?
SOL:
a) 1 km/h = 0.6mph
160 km/h = (160) (0.6)
= 96 mph
10min. What was his average sped in mph?
b) What is the speed in Km/h?
SOL:
a) Time (t) = 1h, 10min
10
= 1h + h
60
7
= h
6
distance
Velocity (v) =
time
30.5
v= 7
6
183
v=
7
= 26.143 mph
b) Average speed = (26.143) (1.60934)
= 42.073km/h.
In most countries outside the United States speed is measured in kilometers per hour (Km/h)
rather than miles per hour(mph). Although the exact conversion from km/h to mph is 0.57, a
conversion factor of 0.6 is generally used because it is easier to remember. For the reverse
conversion a factor of 1.7 is normally used. Perform the following conversions using the
approximate conversion factors.
a) What is the speed in mph of an automobile on the German Autobahn travelling at 160
km/h?
b) What s the speed in km/h of motorcycle travelling at 70mph in the United States?
SOL:
a) 1 km/h = 0.6mph
160 km/h = (160) (0.6)
= 96 mph
