# AQA Physics 9-1 Forces and Motion (exc momentum)

 What is the difference between distance and displacement? Distance is a scalar quantity whereas displacement is a vector quantity State a typical walking speed 1.5 m/s State a typical running speed 3 m/s State a typical cycling speed 6 m/s State the typical speed of sound in air 330 m/s State the typical speed of a car on a motorway 30 m/s Explain why an object moving with constant speed in a circular motion is accelerating Acceleration is the rate of change of velocity.As velocity is a vector it has both a magnitude and a direction. As the direction of an object travelling in a circular motion is constantly changing, then the velocity is also constantly changing, which in turn means it is accelerating. What does a horizontal line on a distance-time graph represent? A stationary object Distance-time graphs What does the gradient of a line represent? speed(or velocity if it was a displacement-time graph) Velocity-time graphs What does a straight line represent? A constant acceleration Velocity-time graphs What does the area under the line represent? Displacement Velocity-time graphs What does the gradient of the line represent? acceleration HIGHER tier only How can you determine the gradient of a curved line? Draw a tangent to the curve at the relevant point and then determine the gradient of the tangent. State Newton's first law of motion When the resultant force acting on an object is zero, the forces are balanced and the object does not accelerate. It remains stationary, or continues to move in a straight line at a constant speed. State Newton's second law of motion Acceleration is  - proportional to the resultant force - inversely proportional to the mass of an object What is meant by the inertia of an object? How easy it is to change the velocity of an object State Newton's third law of motion Every force has an equal and opposite force. These:- act on two separate bodies- are always of the same type What is meant by thinking distance? The distance travelled whilst the driver reacts to a stimulus What is meant by braking distance? The distance travelled between the brakes first being applied and the car stopping. What is meant by stopping distance? The sum of the braking and thinking distances What factor affects both thinking and braking distance? Speed State two factors increasing a driver's reaction time drinking alcoholtaking some types of drugstirednessbeing distracted State two factors increasing a car's braking distance wet or icy road conditionspoorly maintained brakesworn tyreshigh speedloose gravel on the road surface If a vehicle doubles its speed, what effect does this have on braking distance? It quadruples it, since AuthorSilcoatesScience ID345364 Card SetAQA Physics 9-1 Forces and Motion (exc momentum) DescriptionAQA Physics 9-1 Forces and motion Updated2023-05-04T14:23:23Z Show Answers