A car travelled 60 km west in 1.33 h along straigt line , then returned back east for 40 km in 0.67 h . its average velocity

7.29 km/h East

Explanation:

Velocity is distance covered per unit time, with consideration to the direction.

Taking East as positive then West is negative

Velocity when traveling towards West

V=d/t where d is distance and t is time taken. Substituting 60 km dor d and 1.33 for t then

V=-60/1.33=-45.112781954887 km/h West

Velocity when traveling towards East

V=d/t where d is distance and t is time taken. Substituting 40 km dor d and 0.67 for t then

V=40/0.67=59.701492537313 km/h East

Average velocity=(velocity East+West)/2

Average velocity is (59.701492537313+-45.112781954887)/2=7.29 km/h

Since the average is positive, then the direction is East

Therefore, the average velocity is 7.29 km/h East

harry byrd declared organized resistance by southern states would prevent racial integration.

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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