Final answer:
When driving on hills, the driver needs to adjust the power supplied by the engine to overcome the effects of gravity and the incline of the hill.
Step-by-step explanation:
The correct answer is option Physics. When driving on hills, the effects that need to be overcome are gravity and the incline of the hill.
Gravity pulls the car downwards, while the incline of the hill adds an additional force that the car must overcome.
To counteract these effects and maintain a constant speed, the driver must adjust the power supplied by the engine.
On uphill slopes, more power is needed to overcome the increased gravitational force and incline. On downhill slopes, less power is required as gravity aids in pulling the car downwards.
By adjusting the power, the driver can ensure the car maintains the desired speed and overcomes the effects of the hill.