8 Force and motion FCAT

EQ: How does the interaction of forces affect the motion of an object?

Remember the Tumble Car activity

Explain: 1. The speed of the tumble car stayed the same. 2. The picture should show the car with an arrow pointing down representing the force of gravity, and arrow pointing up representing the force exerted by the floor, an arrow pointing forward representing the force of the car motor, and an arrow pointing backwards representing the force of friction. 3. The forces are balanced. My evidence is that the direction and the speed of the car did not change. 4. Suggestions could be : change the speed by increasing the force of friction and change the direction by pushing the car from the side.

Elaborate: A force is a push or a pull on an object. Forces can either be contact forces, which are exerted when objects touch each other, or non-contact forces, which are exerted at a distance. Gravity, electricity and magnetism are all examples of non-contact forces.

Gravity is the force of attraction between objects that have mass Gravity is the force of attraction between objects that have mass. Since all objects have mass, gravity acts between all objects. Mass is a measure of the amount of “stuff” in an object. The strength of gravity between two objects depends on the mass of the objects and the distance between them. The greater the mass of the object, the stronger the gravitational force and the closer the objects are to each other, the stronger the gravitational force.

The force that gravity exerts on an object is measured by weight The force that gravity exerts on an object is measured by weight. Weight is a measure of how much gravity is pulling on an object.

Unlike mass, which stays the same, weight can change depending on where the object is located. For example, your body has the same mass on Earth as it does on the moon, but you weigh about six times more on Earth than you would on the moon.

Electrical force and magnetic force are closely related because they are both caused by negative and positive charges in matter.

Atoms, which make up all matter, contain a positively charged nucleus and a negatively charged cloud of electrons. When charges from one piece of matter interact with those of another piece of matter, they produce both electric and magnetic forces. These forces can be attractive or repulsive.

Whenever a force is applied an object can be affected in several ways. Forces acting on a stationary object can set the object in motion, or they can change a moving object’s speed and/or the direction it is moving at.

The net force on an object is the combination of all the forces acting on it. If the net force is zero, the forces are said to be balanced. When forces are balanced, the speed and direction of an object will stay the same. . The direction of a moving object will always be in a straight line if forces are balanced.

When the net force on an object is greater than zero, the forces are said to be unbalanced. When forces are unbalanced, an object will accelerate in the direction of the force. This means that an object will speed up, slow down and/or change direction due to unbalanced forces.

The speed of an object can be determined by dividing the distance the object traveled by the time it traveled. When objects speed up they are said to have positive acceleration. When objects slow down they are said to have negative acceleration.

One of the main forces that cause objects to have negative acceleration is friction. Friction is the force that opposes motion between two surfaces that are in contact with each other. In addition to slowing objects down, friction is also the force that keeps stationary objects in place.

1. the curved track 2. no 3. in a straight line 4. The marble will travel in a straight line, because that is what happens to motion when forces are balanced.