Friction
What is friction?
The resistance that once surface/ object encounters when moving against each other.
How do you solve for weight?
W= mg or F=mg
A bowling ball and feather when dropped in a vacuum will land at the same time. Why is this true?
There is no air resistance in a vacuum only gravity.
What is Newton's 2nd law?
a= f/m
W=mg F=mg a=f/m f=ma
What is the weight of an object that has a mass of 10kg? Do not forget the units!
100N
What direction is friction in?
Opposing the force acted on an object.
By how much would the weight of an object change if the mass is doubled?
The weight would double.
When is terminal velocity achieved?
When the gravitational force of an object = the air resistance
What happens to the acceleration of an object if the force increases?
The acceleration increases.
W=mg F=mg a=f/m f=ma
What is the mass of an object that has a weight of 130N? Do not forget the units!
13kg
What causes friction?
The imperfections/ microwelds on surfaces rub against each other and create connections.
What is another term to describe an object's weight?
Force due to gravity
500N Upwards direction
What happens to acceleration if the mass decreases?
The acceleration increases.
W=mg F=mg a=f/m f=ma
Daniel is playing soccer. He kicks the 5kg soccer ball with a force of 20N. What is the acceleration of the soccer ball? Do not forget the units!
4m/s2
What is the difference between static and sliding friction?
Static friction is the force acting in order to keep an object at rest. Sliding friction is the force acting against two surfaces that are sliding past each other.
What is the difference between mass and weight? Which will always be the same?
Mass is the amount of matter an object contains- always stays the same
What are two ways that you can increase your air resistance?
Increase surface area or increase speed
The force acting on an object triple and the mass stays the same. How much will the acceleration increase by?
The acceleration will triple.
W=mg F=mg a=f/m f=ma
Riley and Sam are going sledding. Riley pushes Sam with a force of 2N and Same accelerates at 88 m/s2. What is Sam's mass? Do not forget the units!
44kg
Which force will always be greater: Sliding or Static? What does this mean?
Static- the amount of force needed to begin moving an object at rest is greater than the force needed to keep an object in motion.
Explain why an object that has a greater mass has would have more inertia.
An object with a greater mass has a greater force to overcome. This means there will be a greater resistance to change.
Explain what occurs to a sky diver's speed as the jump out a plane, open their parachute and reach terminal velocity.
When the sky diver first jumps, their speed increases rapidly
When they open their parachute their surface increases therefore the air resistance acting on them increases. This causes their speed to decrease.
Eventually the amount of air resistance =gravitational force. They reach terminal velocity.
The acceleration of an object is halved while the amount of force applied to it stays the same. What must have happened to the mass? (Decrease or increase by how much)
the mass was doubled
W=mg F=mg a=f/m f=ma
Joan pushing a crate of toys. The Crate weighs 200N. She pushes the crate with a force of 20N. What is the crates acceleration? Do not forget the units!
1 m/s2