3. SPEED,TIME & DISTANCE
To find speed,
1. if distance is given in metre(m) and time in second (s),
then speed is in metre per second (m/s).
2. if distance is given in kilometre (km) and time in hour
(h), then speed is in kilometre per hour (km/h).
To find distance,
1. if speed is in m/s, time must be in second.
2. if speed is in km/h, time must be in hour.
To find time,
1. if speed is in km/h, distance must be in kilometre.
2. if speed is in m/s, distance must be in metre.
4. SPEED,TIME & DISTANCE
C O N V E R S I O N O F S P E E D
T o c o n v e rt s p e e d fro m k m /h r in to m e tre /s e c o n d m u ltip ly b y
18
5
.
T o c o n v e rt s p e e d fro m m e tre /s e c o n d in to k m /h r m u ltip ly b y .
5
18
5. Time & Distance 1
• If different distance is travelled in different
time then,
If a car travels 50 Km in 1 hour, another 40 Km in 2 hour and another
70 Km in 3 hour then what is average speed of car.
Total Distance Covered = 50 + 40 + 70 = 160 Km
Total Time Taken = 1 + 2 + 3 = 6 hours.
6. Time & Distance 2
• If equal distance is travelled at different
speed.
• If equal distance is travelled at the speed of
A and B then,
A boy goes to his school which is 2 Km away in 10
minutes and returns in 20 mins then what is boy’s
average speed.
Let’s say A = 2/10 = 0.2 km/min
And B = 2/20 = 0.1 km/min
7. Time & Distance 3
• If equal distance is travelled at the speed of A,
B and C then,
If a car divides its total journey in three equal parts and
travels those distances at speed of 60 kmph, 40 kmph and 80
kmph then what is car’s average speed?
Let’s say A = 60, B = 40 and C = 80, then
8.
9. Average Speed
A man on tour travels first 160 km at 64 km/hr and the
next 160 km at 80 km/hr. The average speed for the first
320 km of the tour is:
10. Total Distance
A man complete a journey in 10 hours. He travels first half
of the journey at the rate of 21 km/hr and second half at the
rate of 24 km/hr. find the total journey in km.
11. SPEED,TIME & DISTANCE
E x a m p le : A m a n c o v e rs a c e rta in d is ta n c e b e tw e e n h is h o u s e a n d o ffic e o n s c o o te r.
H a v in g a n a v e ra g e s p e e d o f 1 5 k m /h , h e is la te b y 2 0 m in u te . H o w e v e r, w ith a s p e e d o f
2 0 k m /h r, h e re a c h e s o ffic e 1 0 m in u te s e a rlie r. F in d th e d is ta n c e b e tw e e n h is h o u s e a n d
o ffic e .
R e q u ire d d is ta n c e = 60
1020
1520
2015
= 60
1020
5
2015
= 3 0 k m .
Required distance = timesinDifference
speedsofDifference
speedsofoductPr
12. SPEED,TIME & DISTANCE
Example: A boy goes to school at a speed of 6 km/hr and returns to the home at a speed
of 4 km/hr. If he takes 10 hours in all, what is the distance between the home and the
school?
Required distance = 10
46
46
24 km.
Required distance =
speedstwoofSum
speedsofoductTime Pr2
