Force And Speed Flashcards
What is a force?
A force is something that changes the speed or direction of an object. A famous Scientist called Isaac Newton described forces as we do today so we use the units Newtons to measure forces
What different types of forces are there?
There are many different types of force. Forces can be divided into contact and non-contact forces.
List 3 different types of contact forces and list 2 different types of non-contact forces.
Contact forces include:
• Thrust
• Drag
• Friction
Non-contact forces include:
• Gravity
• Magnetism
What is friction?
Friction is a force that opposes the sliding motion of an object when in contact with another object. All objects stick together to some extent. To move something, you must use enough force to overcome the friction force between the objects.
Give 2 advantages of friction and 2 disadvantages of friction
Advantages
1. Friction allows brakes on a bike or car to work.
2. Friction allows us to walk on the ground without falling.
Disadvantages
1. Friction causes blisters on our feet.
2. Friction causes tyres to wear out
How do you reduce friction?
We use lubrication to reduce friction. Usually this means using oil or grease on the objects so they slide over each other easier. You might put oil on your bike chain to help with this.
Explain the steps in investigating friction in a laboratory.
- Use a spring balance to pull blocks of wood across 3 different surfaces.
- Write down how many newtons are needed to move the block.
- You should notice the amount of newtons is greater for rougher surfaces.
What is mass?
Mass is how much matter is in something. We measure it using a mass balance or bathroom scales and use the units kilograms (kg).
What is weight?
Weight is the force due to gravity that a mass pushes down on the Earth. It is measured in Newtons. The gravitational constant on Earth is roughly 10N/Kg.
What is Hooke’s Law?
Objects that change shape when forces are applied and removed are called elastic. Hooke’s law says that the extension of a spring is directly proportional to the force that is stretching it.
Explain what the graph from Hooke’s Law experiment would be like.
The graph you get will be a straight line. This tells us that the extension and the applied force are directly proportional. If the spring is stretched beyond this point it will not return to its original shape. We say it has exceeded its elastic limit
What is speed?
Speed is the distance travelled by an object in a unit of time.
What is velocity?
Velocity is the speed of an object and the direction it is moving in.
What is acceleration?
Acceleration is the change in velocity of a body in a unit of time.
