Question

1. A tortoise was moving a distance of 100 metres in 15 minutes.What is the average speed of tortoise in km/h.
2. If a sprinter runs a distance of 100 metres in 9.83 seconds,calculate his average speed in km/h?
3. An aircraft travelling at 600km/h accelerates steadily at 10km/h per second.Taking the speed of sound as 1100km/h at the aircraft's altitude,how long will it take to reach the 'sound barrier'.​

Answer 1

Answer:

1. Distance covered by the tortoise = 100 metres

Time taken for covering 100 metres = 15 minutes

• The average speed of the tortoise is to be found

Average speed = Total distance/Total time

Distance in km = 0.1 km

Time in hours = 1/4 hours=0.25 hours

Average speed = 0.1/0.25

Average speed = 0.4 km/h

2. Distance covered by the sprinter = 100 metres

Time taken by the sprinter to cover 100 metres = 9.83 seconds

• The average speed of the sprinter is to be found

Distance covered by the sprinter in km = 0.1 km

Time in hours = 0.002730556 hours

Average speed = 0.1/0.002730556

Average speed = 36.6225 km/h

3. Initial velocity of the aircraft = 600 km/h = 1500/9 m/s

Final velocity = v = 1100 km/h = 2750/9 m/s

Acceleration = 10 km/h

In terms of m/s²=25/9 m/s²

Now using first equation of motion:

V=u+at

2750/9=1500/9+25/9t

1250/9=25/9t

t = 1250/9 × 9/25

t = 50 seconds

The time taken is equal to 50 seconds