Speed = 30 km per hour, Time = 5 min, Distance = ?
Answers
Step-by-step explanation:
Selina solutions
Grade 7
Biology
Mathematics
Physics
Chapters in CONCISE Physics - Middle School - 7
Exercises in Motion
Question 6
Q6) A car travels with speed 30 km h-1 for 30 minute and then with speed 40 km h-1 for one hour. Find :
(a) the total distance travelled by the car (b) the total time of travel, and (c) the average speed of car
Solution
Transcript
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
Answer:
distance is speed × time
D = 30 × 5/60
D = 2.5 km