Question

1. Describe how speed is measured (what are the units)

2. A car moving at a constant speed changes direction. Is the car accelerating? How do you know?

3. How do you calculate speed?

4. A family is traveling south to Florida for a 5 day Disney vacation. The are traveling 105 km per hour during the trip. Is this an example of SPEED OR VELOCITY and how do you know.

5. How do you calculate acceleration?

Answer 1

1.The S.I unit of speed is meter/sec .The bigger unit is Km/hr .

2.Yes, the car is accelerating .

The car is moving with constant speed but at the same time ,it is changing its direction continuously: This refers to non-uniform velocity which further give rise to acceleration.

Acceleration is rate of change of velocity .

3.Speed is defined as distance traveled in a given time .Therefore it can be calculated as : Speed =Distance /Time .

4.Total distance traveled = 105 Km /hr .

This is an example of speed .

The reason being they have not specified the direction in which car is travelling .The only difference between velocity and speed is the mentioning of direction because speed is scalar quantity and velocity is vector .physical quantity .

5.Acceleration can be calculated as : Change of velocity /time