6134723
Description
Flashcards by Mel Hughes, updated more than 1 year ago
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Created by Mel Hughes
over 7 years ago
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| Question | Answer |
| What is the SI unit of force? | Newton, N |
| In what direction does the force of weight always act? | Downwards (or towards (the centre of) the Earth) |
| What is the unit of resultant force? | Newton, N |
| What is the resultant force of a 4N force and a 3N force acting in the same direction? | 7N in the same direction as the two forces |
| What happens to the acceleration of an object as the resultant force on it decreases? | Acceleration decreases |
| What is the resultant force on a car of mass 1000kg if its acceleration is 2m/s2? | 2000N |
| What is the resultant force on a car travelling at a steady speed on a straight horizontal road? | Zero |
| What is the relationship between stopping distance, thinking distance and braking distance? | Stopping distance = thinking distance + braking distance |
| Why does an object dropped in a fluid initially accelerate? | There is a resultant force acting on it |
| What eventually happens to an object falling in a fluid? | It will reach a terminal velocity because the resultant force becomes zero |
| What is an inelastic object? | An inelastic object is one that does not regain its original shape when the forces deforming it are removed |
| A spring has a spring constant of 30 N/m. If the extension is 0.30m, what is the force applied? | 9N |
| How can we tell when a spring has exceeded its limit of proportionality? | The graph of extension against force applied is no longer a straight line |
| Why does making a vehicle more streamlined improve fuel economy? | Less engine and less power are needed to maintain a certain speed. Less fuel is needed so fuel costs are reduced |
| When a vehicle is travelling along a straight road at a steady speed what can you say about the engine force and the air resistance? | The vehicle is not accelerating, so the resultant force on it is zero. So the engine force and air resistance are balanced |
| If you push on a wall with a horizontal force of 15N to the right, what force will the wall exert on you? | 15N to the left |
| What happens to an object moving at a steady speed if the resultant force on it is zero? | The object continues to move at a steady speed in the same direction |
| When will a resultant force cause a deceleration? | When the force is in the opposite direction to the motion |
| What happens to the acceleration of an object as the resultant force on it increases? | The acceleration increases |
| What is the resultant force on a car of mass 1500 kg if its acceleration is 0.5m/s2? | 750N |
| What is the acceleration of a car of mass 2000kg if the resultant force acting in its direction of motion is 800N? | 0.4m/s2 |
| What is the effect of the speed of a vehicle on its stopping distance? | The faster the speed the greater the stopping distance |
| What is terminal velocity? | The final steady speed of an object falling freely through a fluid |
| What is the weight of a person of mass 70kg? | 700N |
| What is an elastic object? | One that goes back to its original size and shape when the force applied to it is removed |
| What does Hooke's law state? | The extension is directly proportional to the force applied, provided the limit of proportionality is not exceeded |
| When a force of 10N is applied to a string it extends by 2.0cm. What is the spring constant of the spring? | 500N/m |
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