P2.1- Motion 4.5 / 5 based on 3 ratings ? PhysicsMotionGCSEAQA Created by: EllaBella888Created on: 19-12-16 21:32 What does the gradient line on a distance–time graph represent? Speed 1 of 28 On a distance–time graph for a car, what happens to the line on the graph when the speed is increased? The line gets steeper (its gradient is increased). 2 of 28 How could we tell from the graph if the car was stationary? The line would be horizontal. 3 of 28 What is the scientific unit of speed? metre per second, or m/s 4 of 28 Write down the equation for calculating the speed of an object moving at constant speed. Speed = distance / time 5 of 28 Why are long-distance vehicles fitted with tachographs? To check that their drivers don’t drive for too long 6 of 28 How can you use a distance–time graph to calculate the speed a lorry was travelling at? By dividing the distance travelled over the time taken 7 of 28 What is velocity? Velocity is speed in a given direction. 8 of 28 Why does the velocity of a plane change as it ‘loops the loop’ at constant speed? The direction of motion changes constantly, so its velocity also changes constantly. 9 of 28 What is acceleration? The change of velocity per second 10 of 28 What is the scientific unit of acceleration? metre per second squared (m/s²) 11 of 28 Write down the equation used to calculate acceleration. Acceleration = change in velocity / time taken 12 of 28 In the alternative equation "a = (v-u)/t" , what do the letters ‘u’ and ‘v’ represent? u is the initial velocity, and v is the final velocity. 13 of 28 What is deceleration? Deceleration is the change in velocity per second when an object slows down. 14 of 28 Give another name for deceleration. Negative acceleration 15 of 28 When an object is accelerating, why does the line on its velocity–time graph go up? Because its velocity is increasing with time 16 of 28 How can we tell from a velocity–time graph whether the acceleration of an object was constant? The line would be straight. 17 of 28 What does the gradient of a line on a velocity–time graph represent? Acceleration 18 of 28 What would the line look like on a velocity–time graph for an object moving at constant speed? It would be straight and horizontal. 19 of 28 If the line goes down, what does this tell us about the motion of the object? It’s slowing down, or decelerating. 20 of 28 How do we find the distance travelled from a velocity–time graph? By calculating the area under the line 21 of 28 What does the gradient of a distance–time graph tell us? The speed of the object 22 of 28 Now use the graph to calculate the speed of the object. Speed = gradient of the line = height of the triangle ÷ base of the triangle = 30 ÷ 10 = 3m/s 23 of 28 What can we tell about the speed of an object if its distance–time graph is not a straight line? The speed of the object is changing. 24 of 28 On a velocity–time graph, what does the height of the line (or triangle) represent? The change of velocity 25 of 28 What does the base of the triangle represent? What does the base of the triangle represent? 26 of 28 Why does the gradient of a velocity–time graph represent acceleration? Because acceleration = change of velocity/time taken, which is the same as finding the gradient of the graph 27 of 28 How would you calculate the distance travelled from the graph? By calculating the area under the line, which is the area of the triangle 28 of 28

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