Question

A motorist drives north for 35.0 min at 85 km/h and then stops for 15 min . He continues travelling north and covers 130 km in 2 hours . What is his total displacement and average velocity

Answer 1

Answer:

Total Displacement : 179.3 Km

Average Velocity : 69.4 m/s

Explanation:

A.T.Q.

Let B be the place at which he stopped

Velocity from A to B, v1 : 85 km/h

Time Taken,

From A to B, t1 : 35 min = 0.58 hr

From B to C, t2 : 2 hr

Displacement,

From A to B, s1 : v1 x t1 = (85 x 0.58) Km = 49.3 Km

From B to C, s2 : 130 Km

Total Time taken : t1 + t2 = 0.58 + 2 = 2.58 hr

Now, Total Displacement : s1 + s2

= 49.3 + 130 Km

= 179.3 Km

Also, Average Velocity : Total Displacement/Total Time Taken

= (s1 + s2)/(t1 + t2)

= 179.3/2.58

= 69.4 m/s