AQA AS Physics - Mechanics and Materials Actual Exam Questions With Answer

AQA AS Physics - Mechanics and Materials Actual Exam Questions With Answer Scalar - ANSWER- A unit with magnitude but no direction. Vector - ANSWER- A unit with magnitude and direction. What are the two methods for adding vectors? - ANSWER- Scale drawings and trigonometry. Free-body force diagrams - ANSWER- Show all the forces acting on a body, each arrow shows the size and the direction of the force. Equilibrium - ANSWER- The forces acting on a body are balances and it is not accelerating (it may be at rest or at a constant velocity). Moment - ANSWER- The turning effect of a force. Moment equation - ANSWER- Force x perpendicular distance from the pivot. Moment unit - ANSWER- Nm If the moments on an object are not balanced, - ANSWER- it will turn. Principle of Moments - ANSWER- For a body to be in equilibrium, the sum of the clockwise moments about a point must be equal to the sum of the anticlockwise moments about the same point. Levers - ANSWER- In a lever an effort force acts against the load force about a rigid object (the lever) attached to a pivot. Couple - ANSWER- A pair of equal and opposite coplanar forces (they act parallel to each other). What does a couple cause? - ANSWER- No resultant linear force, but a turning effect (a moment). The moment created by a couple - ANSWER- The size of the moment depends on the size of the forces and the distance between them. Couple equation - ANSWER- Moment of a couple = size of one force x perpendicular distance between the forces. Centre of mass - ANSWER- The point at which the mass of the object acts. Where is the centre of mass of a uniform, regular solid? - ANSWER- At its centre. The centre of mass can be found through... - ANSWER- Symmetry and experiment (hanging it and drawing a vertical line down, repeating this - where the lines cross is where the centre of mass is). How can centre of mass be used to stabilise objects? - ANSWER- If the line drawn downwards from the centre of mass passes within the base area, then the object will be stable. Free fall - ANSWER- The motion of an object undergoing acceleration due to gravity. The only force acting on an object in free fall - ANSWER- Weight Objects in free fall... - ANSWER- accelerate at the same rate. Newton's first law - ANSWER- An object will remain at rest or at a constant velocity as long as there is no resultant force. If the forces on an object aren't balanced, it will... - ANSWER- accelerate Newton's second law - ANSWER- The resultant force is proportional to the acceleration of the object (F = ma)