how do we know that the bicycle is moving fast

because its speed is great.

i think because of the displacement.there is displacement and a force is applied for great speed.

I f i m wrong pls interuppt me.

To determine if a bicycle is moving fast, you can use a few methods:

1. Observational Method: You can simply observe the movement of the bicycle and compare it to the surrounding objects or people. If the bicycle is passing by them quickly, then it is likely moving fast.

2. Speedometer: Most bicycles nowadays are equipped with speedometers. These devices measure the speed of the bicycle based on factors like wheel rotations or GPS data. You can check the speedometer reading to know if the bicycle is moving fast.

3. GPS Tracking Apps: If you have a smartphone with a GPS tracking app, it can measure the speed of the bicycle. These apps use satellite signals to calculate the speed accurately.

4. Doppler Effect: If you are stationary and the bicycle is moving towards or away from you, you might notice a change in the pitch of the sound produced by the bicycle. As the bicycle approaches you, the pitch will be higher, and as it moves away, the pitch will be lower. These pitch changes can be an indication of the bicycle's speed.

5. Time and Distance: Another method is to measure the time it takes the bicycle to cover a certain distance. For example, if you know the distance between two landmarks, you can use a stopwatch to measure the time it takes for the bicycle to travel that distance. Then, by dividing the distance by the time, you can calculate the speed of the bicycle.

Remember, it's important to use multiple methods for accuracy and to consider factors such as road conditions and terrain, as they may affect the perceived speed of the bicycle.