OCR A Physics A-level Topic 3.2: Forces in Action

The speed of the object and the object's cross-sectional area.

The drag force is proportional to the square of the speed.

The object reaches terminal velocity.

<p>The drag forces reduce the net force acting on the object, resulting in a decrease in acceleration.</p> Signup and view all the answers

<p>The acceleration of the object is proportional to the net force acting on it.</p> Signup and view all the answers

<p>The SI unit for force is kgms-2, and one Newton is defined as the force that will give a mass of 1kg an acceleration of 1 ms-2.</p> Signup and view all the answers

<p>The formula for weight is W = mg, where m is the mass of the object and g is the acceleration due to gravity.</p> Signup and view all the answers

<p>Friction is the force that arises when two surfaces rub against each other, while drag is the resistive force on an object travelling through a fluid.</p> Signup and view all the answers

<p>Terminal velocity is the maximum velocity an object can reach as it falls through a fluid, and it is related to the drag force, which opposes the object's motion.</p> Signup and view all the answers

<p>Free fall is the motion of an object under the sole influence of gravity, while the acceleration due to gravity is the rate of acceleration of an object in free fall.</p> Signup and view all the answers

<p>𝑝𝑝 = ℎ𝜌𝜌𝜌𝜌𝐴𝐴</p> Signup and view all the answers

<p>The upthrust exerted on a body immersed in fluid is equal to the weight of the fluid that the body displaces.</p> Signup and view all the answers

<p>The weight of the object is equal to the weight of the fluid it displaces.</p> Signup and view all the answers

<p>Upthrust</p> Signup and view all the answers

<p>The net force in each direction must be 0.</p> Signup and view all the answers

<p>The object will sink.</p> Signup and view all the answers

<p>The centre of mass.</p> Signup and view all the answers

<p>A plumb bob is suspended from a string directly in front of the object, and a straight line along the string is drawn on to the object. The object is then suspended from another point, and another line is drawn. The intersection of these lines is the centre of mass of the object.</p> Signup and view all the answers

<p>Letters to represent unknown forces or distances, along with Pythagoras' theorem and the sine and cosine rules.</p> Signup and view all the answers

<p>The centre of mass and centre of gravity coincide.</p> Signup and view all the answers

<p>Density is defined as the mass per unit volume, and its SI unit is kgm-3.</p> Signup and view all the answers

<p>The volume of an irregular solid object is measured by placing it in water inside a measuring cylinder, and the change in volume when the object is fully submerged is equal to the volume of the object.</p> Signup and view all the answers

<p>Pressure is defined as the normal force exerted on a surface per unit cross-sectional area, and its unit is Nm-2 or Pascal (Pa).</p> Signup and view all the answers

<p>The formula is p = hρg, where p is the pressure, h is the height of the fluid column, ρ is the density of the fluid, and g is the acceleration of free fall.</p> Signup and view all the answers

<p>The pressure exerted by a fluid is due to the weight of the fluid, and the two are directly proportional.</p> Signup and view all the answers

<p>It experiences a drag force, which is a frictional force that opposes motion.</p> Signup and view all the answers

<p>It is often easier to resolve the forces into components acting parallel and perpendicular to the slope, rather than horizontally and vertically, to calculate the net force.</p> Signup and view all the answers

<p>The net force is proportional to the acceleration of the object, as described by F = ma.</p> Signup and view all the answers

<p>The weight of an object is the product of its mass and the acceleration due to gravity.</p> Signup and view all the answers

<p>Terminal velocity.</p> Signup and view all the answers

<p>0</p> Signup and view all the answers

<p>The distance travelled between each time interval becomes the same</p> Signup and view all the answers

<p>To increase the accuracy of the experiment</p> Signup and view all the answers

<p>M = F × d</p> Signup and view all the answers

<p>It opposes the acceleration due to gravity, slowing down the object</p> Signup and view all the answers

<p>The weight of the object affects the magnitude of the drag force required to reach terminal velocity</p> Signup and view all the answers

<p>It allows for the measurement of time intervals</p> Signup and view all the answers

<p>It remains constant</p> Signup and view all the answers

<p>The drag force increases with velocity</p> Signup and view all the answers

<p>To produce 50 dots per second on the tape, which travels at the same speed as the ball bearing</p> Signup and view all the answers