1. does the speedometer of a car read average speed or instantaneous speed? how do you know? 2. if the…
1. does the speedometer of a car read average speed or instantaneous speed? how do you know? 2. if the speedometer of your car reads a constant speed of 40km/hr, can you say 100% for sure that the car has a constant velocity? explain your answer. 3. what two controls on a car cause a change in speed? 4. what control causes a change in velocity? 5. what is the acceleration of a car that travels in a straight line at a constant speed? 6. describe a situation in which you can accelerate even though your speed doesnt change.
Answer
Brief Explanations:
The speedometer of a car measures instantaneous speed at a particular moment. It doesn't directly measure average speed over a time - interval. So, it reads instantaneous speed.
Answer:
The speedometer of a car reads instantaneous speed.
Brief Explanations:
A constant reading on the speedometer means the magnitude of the velocity (speed) is constant. But velocity is a vector with both magnitude and direction. Without information about direction, we can't be 100% sure of constant velocity.
Answer:
No, we can't say 100% for sure that the car has a constant velocity as velocity is a vector and we need to know the direction is constant too.
Brief Explanations:
The accelerator (gas pedal) increases speed and the brake decreases speed. These are the two main controls that cause a change in speed.
Answer:
The accelerator (gas pedal) and the brake are the two controls on a car that cause a change in speed.
Brief Explanations:
The steering wheel changes the direction of the car. Since velocity is a vector with magnitude and direction, changing direction changes velocity. Also, the accelerator and brake change the magnitude of velocity.
Answer:
The steering wheel (changes direction), the accelerator (increases speed/magnitude of velocity), and the brake (decreases speed/magnitude of velocity) are the controls that cause a change in velocity.
Brief Explanations:
Acceleration is a change in velocity over time. If a car is moving in a straight - line at a constant speed, its speed isn't changing but if it changes direction (e.g., going around a circular track at a constant speed), there is acceleration due to the change in direction of velocity.
Answer:
Acceleration of a car moving in a straight line at a constant speed can be non - zero if it changes direction (e.g., moving on a circular path at constant speed).
Brief Explanations:
When a car moves in a circular path at a constant speed, its speed remains the same but its direction is constantly changing. Since velocity is a vector (has magnitude and direction), the changing direction means there is acceleration.
Answer:
A car moving in a circular path at a constant speed is accelerating because its direction is changing, and acceleration is a change in velocity (which includes direction change).