17. Which of the following are inertial reference frames? Explain.

a. A car driving at steady speed on a straight and level road.

b. A car driving at steady speed up a 10° incline.

c. A car speeding up after leaving a stop sign.

d. A car driving at steady speed around a curve.

in question they give the different 4 option and asked us to find the which are in inertial reference frames and then given explanation why they consider in inertial reference frames or why not.

Here, inertial reference frame means where the object is not accelerating and follows the Newton`s law or in other word where the Newton`s law valid.

object is also consider in inertial reference frame if it is moving with constant velocity.

object is consider in inertial reference frame if the net force acting on the object is zero and it is follow the Newton`s second law, which means that the acceleration of the object is also zero.

1. A car driving at steady speed on a straight and level road.

Here car driving at steady speed which means that car moving at constant speed and follow the Newton's law of motion because of this reason here consider that the car is in inertial reference frame.

Therefor, the car is in inertial reference frame.

2. A car driving at steady speed up a 10° incline.

car is consider in inertial reference frame because the net force acting on the car is zero and it is follow the Newton's second law, which means that the acceleration of the car is also zero.

Therefor, consider that car which have steady up a ${10}^{°}$incline in inertial reference frame.

3. A car speeding up after leaving a stop sign.

Here after stop the car when car start to moving it have some acceleration which means net force on the car is not zero and not follow the Newton`s second law.

Therefor, the car is not in inertial reference frame.

4. A car driving at steady speed around a curve.

Here car moving in curve means that at some time when car near the curve little bit the speed of car change which means not moving at constant velocity and not follow the Newton`s law.

Therefor, the car is not in inertial reference frame.