11824722
Descrição
FlashCards por Noshin Nuhash, atualizado more than 1 year ago
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Criado por Noshin Nuhash
mais de 6 anos atrás
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| Questão | Responda |
| What do free body diagrams show? | Show all the forces acting on an object. |
| What forces act on a skydiver? | A skydiver's weight acts on him pulling him towards the ground and drag (air resistance) also acts on him, in the opposite direction to his motion. |
| What do the size of the arrows show? | Show the relative magnitude of the forces. |
| What does the direction of the arrow show? | Show the direction of the forces acting on the object. |
| What is a resultant force? | A resultant force is an overall force on a point or object. |
| What happens if you have a number of forces acting at a single point? | You can replace them with a single force (so long as the single force has the same effect as the original forces together). |
| What is this single force called? | Resultant force. |
| How to calculate the resultant force? | Consider the horizontal and vertical directions separately then subtract any going in the opposite direction. |
| What happens if a resultant force moves an object? | Work is done. |
| What happens when a force moves an object through a distance? | Energy is transferred and work is done on the object. |
| How do you keep something moving if there are frictional forces? | A force must be applied. |
| What does the thing applying the force need? | A source of energy (like fuel or food). |
| Why does the force do 'work'? | To move the object and energy is transferred from one store to another. |
| When is work done? | When energy is transferred 'usefully' (e.g lifting a load) or is 'wasted'. |
| When are you doing work against frictional forces? | When you push something along a rough surface (like a carpet). |
| How is energy being transferred? | To the kinetic energy store of the object because it starts moving, but some is also being transferred to thermal energy stores due to the friction. |
| What does this cause the overall temperature of the object to do? | Increase |
| Equation: | Work done (J) = Force (N) x Distance (moved along the line of action of the force) (m) |
| How to convert joules to newton metres? | 1 J = 1 Nm |
| What is terminal velocity? | When the object's weight is balanced by the air resistance. There is no resultant force and the object reaches a steady speed. |
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