# Essay on Physics coursework - marked A* (60/64marks)

6868 WordsMar 22, 201428 Pages
The factors that affect the motion of a falling object Scientific Knowledge When an object falls, many forces are acted upon it: gravity, friction, air resistance and, if in the water, up thrust. When an object starts to fall, gravity over powers air resistance, however, as an object starts to reach terminal velocity (its maximum speed) the opposite forces start to even out until they are equal. Some people believe that if the forces are balanced then the object has stopped moving, meanwhile they could also just be moving at a constant speed (its terminal velocity). All free-falling objects accelerate at the same speed no matter what their mass is (9.8m/s²). There are two calculations you need for this investigation, no matter which…show more content…
This is because the weight increases as the cube of the size of an object, but the air resistance (drag) only increases as the square of the size, so the bigger the object is, the faster it will fall (or to be more precise, it has a higher terminal velocity.) The surface area can affect the motion of the falling object because it is has more air resistance pushing against it. Because there is more air resistance pushing against a larger object, it will fall so because it is making the downward force (gravity) weaker since there is now a larger force counteracting that first force. An object with a larger surface area will fall slower (have a smaller velocity) because it means there is a large area for air to come into contact with to produce that counteracting force called air resistance. Another factor that can affect the motion of a falling object is the viscosity of the liquid that it is falling through. Viscosity of liquid means how thick the liquid is. The higher the viscosity of the liquid, the more the liquid resists the object which is falling through it. This means that it will take a longer amount of time for the object to fall; meaning the velocity of the object will be very small. A further factor that can affect the motion of a falling object is the height from which the object is dropped from. Obviously, if an object is dropped from a greater height, it will take longer to reach the ground than the same object to reach the