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Several forces are involved when the model is at rest and when it is moving. The model has weight, and the wound-up rubber band exerts tension on the axle. The weight is described in terms of the gravitational force. The weight of the car has to be overcome to get it to move. Newton’s first law states that an object will remain at rest unless an unbalanced force acts on it. Also, an object will continue to move unless an unbalanced force acts on it. Inertia is the resistance to motion, and friction causes a moving object to slow down or stop. | Lecture # 20 SCIENCE 1 ASSOCIATE DEGREE IN EDUCATION Force and Motion continue . Background information Several forces are involved when the model is at rest and when it is moving. The model has weight, and the wound-up rubber band exerts tension on the axle. The weight is described in terms of the gravitational force. The weight of the car has to be overcome to get it to move. Newton’s first law states that an object will remain at rest unless an unbalanced force acts on it. Also, an object will continue to move unless an unbalanced force acts on it. Inertia is the resistance to motion, and friction causes a moving object to slow down or stop. A key idea here is the notion of unbalanced forces. In the model car example, several forces are involved. There is gravitational force, normal force, a tension force, a frictional force, and the force of air resistance, which in this case is negligible. A force is a push or pull resulting from one object acting on another object. Forces have magnitude and direction. The gravitational force is gravity acting on the mass of the car. The Earth, which is one object, is attracting the model car, which is another object. The direction of this force is downward towards the centre of the Earth. At the same time, there is another force (normal force), which is the floor pushing upward on the wheels of the car. The tension force is the wound-up rubber band. It acts to turn the axle of the model car, causing the wheels to rotate and move the car forward. The magnitude and direction of this force overcome the downward force of gravity. When the model car is moving, the force of friction eventually causes the model car to come to rest. Friction acts in the opposite direction of the movement of the car. Background information continue A tension force, or an applied force, (when the model car is pushed by hand or a magnet to illustrate that forces do not require physical contact) can overcome inertia. This results in unbalanced . | Lecture # 20 SCIENCE 1 ASSOCIATE DEGREE IN EDUCATION Force and Motion continue . Background information Several forces are involved when the model is at rest and when it is moving. The model has weight, and the wound-up rubber band exerts tension on the axle. The weight is described in terms of the gravitational force. The weight of the car has to be overcome to get it to move. Newton’s first law states that an object will remain at rest unless an unbalanced force acts on it. Also, an object will continue to move unless an unbalanced force acts on it. Inertia is the resistance to motion, and friction causes a moving object to slow down or stop. A key idea here is the notion of unbalanced forces. In the model car example, several forces are involved. There is gravitational force, normal force, a tension force, a frictional force, and the force of air resistance, which in this case is negligible. A force is a push or pull resulting from one object acting on another object. Forces .
