Question

Two points,L and N are 160 m apart. M lies on the straight line joining L and N. An object travels from L to M at an average speed of 10 m/s in 6 seconds and then from M to N at an average speed of 25 m/s. Find the average speed of the object for it's entire journey from L to N.

Answer 1

16m/s

Explanation:

If the object travels from L to M at an average speed of 10 m/s in 6 seconds, we can get the distance LM using the formula;

Speed = Distance/Time

Distance = Speed * Time

Distance = 10 * 6

Distance = 60m

Hence LM = 60m

Since LN = LM + MN

160 = 60 + MN

MN = 160-60

MN = 100m

If the object moves from M to N at an average speed of 25 m/s througj a distance od 100m, the time taken will be expressed as;

Time = distance/speed

Time = 100/25

Time = 4secs

Total time taken to move from L to N is 6secs + 4secs = 10secs

The average speed of the object for it's entire journey from L to N will be:

Average speed = Distance LN/10

Average speed for the entire journey = 160/10 = 16m/s

Hence the average speed of the object for it's entire journey from L to N is 16m/s