6. A car travels with speed 30 km
and then with speed 40 km for one hour
Find.
(a) the total distance travelled by the
(b) the total time of travel, and
(c) the average speed of
Answers
Answer:
Speed of car for first 30 minutes = 30 km h^{-1}
Speed of car for next 1 hour = 40 km h^{-1}
(a) total distance travelled by the car
First case
Speed = distance / time
distance = speed x time
= 30 x 0.5 ---- (30 min = 0.5 hour)
= 15 km ---- (i)
Second case
speed = 40 km h^{-1}
distance = 40 km x 1
= 40 km ---- (ii)
Adding (i) and (ii)
Total distance = 15 km + 40 km
= 55 km
(b) total time of travel = 0.5 hr + 1.0 hr = 1.5 hr
(c) average speed = total distance travelled/total time taken
= 5.5 km/ 1.5 hr
= 36.67 km h^{-1}
Answer:
Solution:
Speed of car for first 30 minutes = 30 km h^{-1}h
−1
Speed of car for next 1 hour = 40 km h^{-1}h
−1
(a) total distance travelled by the car
First case
Speed = distance / time
distance = speed x time
= 30 x 0.5 ---- (30 min = 0.5 hour)
= 15 km ---- (i)
Second case
speed = 40 km h^{-1}h
−1
distance = 40 km x 1
= 40 km ---- (ii)
Adding (i) and (ii)
Total distance = 15 km + 40 km
= 55 km
(b) total time of travel = 0.5 hr + 1.0 hr = 1.5 hr
(c) average speed = total distance travelled/total time taken
= 5.5 km/ 1.5 hr
= 36.67 km h^{-1}h
−1