2. Which of the following statements best explains the key difference between velocity and speed?

Question

2. Which of the following statements best explains the key difference between velocity and speed?

a. Velocity must be reported in m/s, but speed can have other distance time units.
b. Velocity depends on direction, speed does not.
c. Objects can have different speeds if they are moving with the same velocities, but not different velocities if they are moving with the same speeds.
d. Due to Earth’s gravity, an object’s velocity will always be slightly larger than its speed.

Answer 1

B. Velocity is a vector, meaning it has magnitude (size) and direction. Speed is a scaler, therefore does not depend on direction.

Answer 2

Velocity comprises two parts: speed and direction. This is sometimes written as: vx = s cos(theta); where vx = velocity along the X axis, s = speed, and theta is a direction angle relative to the X axis (the east-west direction).

For example, if your car is traveling at a speedometer speed of s = 60 mph and you are traveling south on I5, you could say your velocity along the X axis (east-west direction) is vx = s cos(theta) = 60 cos(-90 deg) = 60*0 = 0 mph east-west. This is good, because I5 does not go east-west and if your car were going that direction, you'd go off the cliff.

Similarly, vy = s sin(theta), where vy is the north-south (Y axis) direction of your car's velocity. Here, vy = 60 sin(-90) when going south on I5. What would your north-south velocity work out to be? (Be careful with the signs, we are using minus 90 degrees here.)

Anyway, b's the answer because speed is scalar and velocity is vector.

Answer 3

B: speed is a scalar, velocity is a vector, which is a scalar plus a direction

Answer 4

b. velocity depends on direction, speed does not.

Answer 5

I agree with B but you are taking a test on here aren't you!!!

Answer 6

B is the right answer dude!

Answer 7

I would say B.