the kinetic molecular theory states the following.composition of gas involves large number of particles known as molecules are randomly in continuous motion. there is large difference in the size of gas molecules and distance between gas molecules. therefore, gas molecules have negligible volume. gases have weak intermolecular forces of attraction or repulsion. therefore, intermolecular forces in gases are negligible. gas molecules randomly collide on the walls of a container without any change in the average kinetic energy of the molecules. the average kinetic energy of any gas depends only on the temperature as at a particular temperature all gas molecules will have same average kinetic energy.
it is known that particles of a gas can never travel in a straight line as rapidly move in all the directions.
therefore, the particles in a gas travel in straight lines in a continuous, random motion is an example of the kinetic-molecular theory not holding true for a gas.
refer newton's law of cooling effect on google ✌