Answer:
B, C, D are valid assumptions
Explanation:
In each stage the acceleration of the car varies because the velocity of car varies in each stage. At first, the acceleration of the car is moving slowly.
Then, driver realizes that he is late so the acceleration of the car increases he hits the gas.
Finally, the acceleration decreases when he sees the police car.
In the first state when driver do not know, that he is late, he will drive with a constant velocity as any one does.
When the driver hits the gas and he does not know about the police vehicle, even then he may drive with constant velocity or he may accelerate the car due to fear of being caught.
In the last part of motion when driver see the police car, even than he may accelerate the car, but acceleration will be constant throughout the motion is not possible, or even than he may continue with constant velocity.
Hence, there are only three assumptions are valid.
B. During each of the three different stages of its motion, the car is moving with constant velocity.
C . The highway is straight.
D. The highway is level.
Note that the rate of change of speed is equal to the acceleration. The acceleration is constant if change in velocity of particle is equal in equal interval of time.
