How do I solve these physics problems, I've tried solving them with no luck?

S

sidd0123

New member
I'm a beginner at physics and don't understand it what so ever. We have summer homework in physics and i dont get the following:

An automobile travels on a straight road for 40 km at 30km/h. It then continues in the same direction for another 40 km at 60km/h.

a) What is the average velocity of the car during this 80km trip? (Assume its moving in the positive direction)

b) What is the average speed?
 
The difference between velocity and speed is that velocity has direction. In this problem the direction doesn't change so you just take the average of the two speeds for both velocity and speed.
 
A) (30+80)/2 = +55 km/h
Velocity is considered a vector so if it is moving in the positive direction then it must be positive. Vectors must have a +/- sign.

B) 55 km/h
Speed is basically the same concept as velocity but it is not a vector. When calculating speed, the direction(s) the object is moving doesn't matter.
 
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