Riding the Bus
Newton’s 1st Law
You get on a bus and stand up. When the bus is stationary you feel no force, when the bus accelerates you feel a backwards force. You want to stay where you are but the bus forces you to move. When the bus is at a constant speed you feel no forwards or backwards forces. The bus slows down and you feel a forwards force. You want to keep moving at the same speed but the bus is slowing down so you fall forwards. If the bus turns left you want to keep moving in a straight line so you are forced to the right (in comparison to the bus). If the bus turns right you want to keep moving in a straight line so you are forced left (in comparison to the bus).
Newton’s 2nd Law
As more people get on the bus its mass increases, if the driving force of the bus’s engine is constant we can see that it takes longer for the bus to gain speed.
Newton’s 3rd Law
As you stand on the bus you are pushing down on the floor with a force that is equal to your weight. If this was the only force acting you would begin to move through the floor. The floor is exerting a force of equal magnitude but upwards (in the opposite direction).