Answer:
the world record for the hundred-meters dash is about 10m/s --> speed
the wind today is 30 km/h from the north-west --> velocity
a 200,000 kg train was traveling north at 70 km/h when it derailed --> velocity
a car was issued a ticket for traveling at 140 km/h on the interstate --> speed
Step-by-step explanation:
Let's remind the difference between speed and velocity first:
- The speed of an object is the ratio between the distance traveled by the object and the time taken. It is a scalar, so it has only a magnitude
- The velocity of an object is a vector whose magnitude is equal to the ratio between the displacement of the object and the time taken, and a direction given by the direction of motion. So, velocity has both magnitude and direction.
Let's analyze now each option:
the world record for the hundred-meters dash is about 10m/s --> this has only a magnitude (10 m/s), so it is a speed
the wind today is 30 km/h from the north-west --> this has both a magnitude (30 km/h) and a direction (north-west), so it is a velocity
a 200,000 kg train was traveling north at 70 km/h when it derailed --> this has both magnitude (70 km/h) and direction (north), so it is a velocity
a car was issued a ticket for traveling at 140 km/h on the interstate --> this has only a magnitude (140 km/h), so it is a speed