Advertisements
Advertisements
प्रश्न
Abdul, while driving to school, computes the average speed for his trip to be 20 km h−1. On his return trip along the same route, there is less traffic and the average speed is 30 km h−1. What is the average speed for Abdul’s trip?
Advertisements
उत्तर
Let the school be at a distance of x km. If
t1 is the time taken to reach the school, then
`t_1 = "distance"/"average speed" = x/20`
If t2 is the time taken to reach back, then
`t_2 = "distance"/"average speed" = x/30`
Total time,
t = `t_1 + t_2`
= `x/20 + x/30 `
= `x [1/20 + 1/30]`
= `(5x)/60`
= `x/12`
Total distance x + x = 2x
Average speed = `"total distance"/"total time"`
= `(2x)/(x/12)`
= 24 km h-1
APPEARS IN
संबंधित प्रश्न
Joseph jogs from one end A to the other end B of a straight 300 m road in 2 minutes 30 seconds and then turns around and jogs 100 m back to point C in another 1 minute. What are Joseph’s average speeds and velocities in jogging?
- from A to B and
- from A to C?
Change the speed of 6 m/s into km/h.
A snail covers a distance of 100 metres in 50 hours. Calculate the average speed of snail in km/h.
A tortoise moves a distance of 100 metres in 15 minutes. What is the average speed of tortoise in km/h ?
Give one example of a motion where an object does not change its speed but its direction of motion changes continuously.
Give an example of motion in which the average speed is not zero but the average velocity is zero.
Give one example of following motion :
Variable velocity
Arrange the following speeds in increasing order.
10 m s-1, 1 km min-1 and 18 km h-1.
Write down the type of motion of a body along with the A – O – B of the following distance – time graph.
How many variables are present in each equation of motion?
