How do force affect the design of transportation in the modern world?…
How do force affect the design of transportation in the modern world?
Newton's First Law
An object at rest will stay at rest unless acted on by a force. An object will continue to travel at a constant speed in a straight line unless acted on by a force
The skater was travelling along the path on his board. He crashed into the fountain so a force acted on his skateboard causing it to stop. The skater was not acted on by a force so he kept moving forward at the same speed into the fountain.
A country train full of passengers is running behind schedule and is travelling at a fast speed. Passing through farms and fields, a cow walks onto the tracks. The train driver hits the emergency brakes and everyone on the train keeps moving and is thrown forward. The behavior of the passenger can be explained by Newton's first law of motion.
In space, the gravity is almost 0 and no external forces are present. If in space, someone hits a cricket ball, the ball only has kinetic energy - due to its motion. It neither loses energy nor gains it because there are no net external forces and therefore will continue to travel at this speed until is acted upon by a different force.
Newton’s 1st law deals with net forces to determine whether an object will move or remain stationary. The two (or more) forces in this case are acting on the SAME object. These forces CAN CANCEL EACH OTHER (depending on direction and size) to give a net force.
Newton's Third Law
Equal in size, opposite in direction
Action: You apply a force to the floor as a result of your weight.
Reaction: The floor applies an equal force on you in the opposite direction
Action: The baseball pushes the bat to the left;
Reaction: The bat pushes the baseball to the right.
For every ‘action’ force there is an equal and opposite ‘reaction’ force
Forces in pairs, action and reaction
Newton's 3rd law deals with forces on TWO DIFFERENT OBJECTS. The two forces have the same strength, and work in opposite directions to the other. THEY DO NOT CANCEL EACH OTHER.
Newton's Second Law
The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to the mass.
Force = a push or a pull (N)
Mass = the amount of matter in an object (kg)
Acceleration = the change in speed of an object (m/s2)
Force = mass x acceleration
A car has run out of fuel and needs to be pushed off the road. One man pushes the car and his friend comes to help. There is now twice the force resulting in twice the acceleration. If the man has a van, the mass would be bigger resulting in a lower acceleration
A person in 3 circumstances is applying the same amount of force to 1, 2 and 3 bricks. The greater amount of mass being pushed, the lower the acceleration. As mass is inversely proportional to the acceleration, the more bricks, the slower they are being pushed.
Force is directly proportional to the acceleration.
Mass is inversely proportional to the acceleration.