click below
click below
Normal Size Small Size show me how
Physics P4
Explaining Motion
Question | Answer |
---|---|
What does velocity tell you? | Speed and direction of travel. |
How it velocity measured? | Changes in distance in one direction is described as positive and changes in the opposite direction are described as negative. |
What do you need to calculate an objects speed? | Distance and Time |
How can you calculate speed? | Speed=Distance/Time |
What are the two different ways of measuring speed? | Instantaneous and average speed |
What is the instantaneous velocity? | The instantaneous speed with an indication of direction. |
What does it mean is happening if the line of a distance-time graph is curved? | The speed of an object is moving. |
What does the gradient of a distance-time graph represent? | How quickly it is increasing in speed (accelerating) |
What are speed-time graphs in lorry tachographs used for? | To make sure they don't exceed the speed limit and rest for suitable amounts of time. |
Can a velocity-time graph have negative values for the velocity axis? | Yes |
How do you measure acceleration? | Acceleration=Change in speed/Time taken |
The forces in an interaction pair are... | Equal in size and opposite in direction and they act on different objects. |
Name three examples of forces in action. | Gravity (weight) Air resistance (drag) Rocket and jet engines |
How do people walk? | By applying a force on to the earth and having an equal and opposite force generated. The person moves because they have a much smaller mass than the Earth. |
What is friction? | The resistance force between two surfaces as they move against each other. |
What does the size of an arrow represent in a forces diagram? | The size of the force. |
What does the direction of an arrow represent in a forces diagram? | The direction the forced is acting in. |
The overall effect of two or more forces is called the... | Resultant force. |
What is momentum? | The measure of the motion of an object. |
How can you calculate momentum? | Momentum = Mass x Velocity |
If the resultant force acting on an object is not zero it will... | Cause a change of momentum. |
Collision's can cause a change in an object's... | Momentum |
If the change in momentum is spread out over a longer period of time, the resultant force will be smaller/larger? | Smaller |
The force of the impact on the human body can be reduced by increasing the... | Time of impact |
What are the two forces that cars and bicycles have? | Driving force and Counter force |
What does the amount of kinetic energy that an object has rely on? | Mass and velocity |
Kinetic energy can be found by... | Kinetic energy= 1/2 x Mass x Velocity |
What are the two forces that oppose motion when an object falls? | Air resistance and Gravity |
When work is done on an object, the object losses/gains energy? | Gains |
When work is done by an object, the object losses/gains energy? | Losses |
The amount of work done is the same as... | the amount of energy transferred. |
How do you calculate the work done? | Work done= Force x Distance |
What does the gravitational potential energy depend on? | Mass and height above ground |