Answer:
TRUE
Step-by-step explanation:
When we throw a penny upwards the due to law of inertia we can say that penny will go upwards with the speed by which we thrown it upwards but it will also move in the direction in which we are moving horizontally.
So the motion of penny with respect to the person who throw it upwards is always zero in the direction of motion if the plane is moving at constant speed.
So here we can generalize it by saying that all the particles which exist inside the plane is moving in same direction with same speed as that the speed of plane so all appears at rest with respect to that person.
So when we throw a penny upwards the it appears to us to move in upwards direction.