A researcher is investigating the braking performance and energy efficiency of a prototype electric cargo bicycle.
The researcher measures the stopping distance of the electric cargo bicycle when the emergency brakes are applied at a speed of 20 km/h20\text{ km/h}20 km/h. The results of three trials are shown in the table below:
| Trial number | Stopping distance (m) |
|---|---|
| 1 | 4.3 |
| 2 | 4.6 |
| 3 | 11.2 |
(i) Calculate the mean stopping distance of the electric cargo bicycle. If you identify an anomalous result, omit it from your calculation.
The total mass of the electric cargo bicycle and its rider is 140 kg140\text{ kg}140 kg. The bicycle climbs a hill of vertical height 6.5 m6.5\text{ m}6.5 m.
Calculate the gain in gravitational potential energy of the bicycle and rider. Take the gravitational field strength as 10 N/kg10\text{ N/kg}10 N/kg.
On a flat, straight section of the cycle path, the electric bicycle accelerates from rest to its top speed of 5 m/s5\text{ m/s}5 m/s.
Estimate the acceleration of the bicycle by choosing a realistic time taken for this acceleration. Use the equation: acceleration=change in velocitytime\text{acceleration} = \frac{\text{change in velocity}}{\text{time}}acceleration=timechange in velocity