Contact Forces
What is a contact force? Give an example.
A contact force is a type of force that occurs when two objects are physically touching each other. (Need an example)
What is a non-contact force? Give one example.
A non-contact force is a type of force that acts on an object without any physical contact between the objects involved. Include an example.
Why is ice more slippery than carpet
Ice has less friction than carpet causing it to be slippery
True or False:
An object travelling at a constant speed and direction has no forces acting on it.
False - the forces acting on it are balanced
What is an independent variable? Provide an example from a simple experiment.
Something that is changed in the experiment. Example.
Give two examples of contact forces and explain how they act on objects.
Any two examples
How does gravity act as a non-contact force between the Earth and an object?
Weight on object, gravitational field, gravitational force
Why is it easier to slide a puck across an ice rink than across a rough concrete path?
Ice is smoother than concrete, so there is less friction between the puck and the ice. Less friction means the puck can move more easily and travel further.
Varying answers
Define a dependent variable. Give an example.
A dependent variable is the factor in an experiment that is measured so see the effect of the independent variable. With an example.
Compare and contrast contact forces with non-contact forces. Provide examples for each.
Contact involves a force where objects are physically touching whilst non-contact involves a force without two objects physically touching
Compare and contrast gravitational force and magnetic force as types of non-contact forces. Provide an example of each.
Gravitational Force: The force that causes a dropped ball to fall to the ground. The Earth pulls the ball towards its center due to gravity.
Magnetic Force: A refrigerator magnet sticking to a metal surface. The magnet exerts a magnetic force on the metal, causing attraction.
A cyclist notices that their bike travels faster after the chain has been oiled. Explain why.
Oil reduces friction between the moving parts of the chain. With less friction, less energy is wasted, allowing the bike to move more efficiently and travel faster.
Explain why an astronaut can jump higher on the Moon than on Earth. Use your understanding of gravity in your answer.
The Moon has less gravity than Earth. Gravity is the force that pulls objects towards the ground. Because the Moon's gravitational pull is weaker, the astronaut is pulled down with less force and can jump higher and stay in the air for longer.
In a study measuring the effect of sunlight on plant growth, identify the independent variable, the dependent variable, and one controlled variable.
Independent: Different sunlight intensities
Dependent: Stem length
Controlled: Same type of plant
A 10 kg box is pushed along the floor with a force of 50 N. If the frictional force opposing the motion is 20 N, what is the net force acting on the box?
30N
Explain why two magnets either attract or repel each other without touching. What determines the direction of the force between them?
The magnetic force between the 2 pull the 2 objects close to each other
A soccer player wears boots with studs on the bottom. Explain how the studs help the player run and change direction.
The studs increase friction between the boots and the ground. This gives the player better grip, making it easier to run, stop, and change direction without slipping.
Explain why the crumpled paper falls faster than the flat sheet of paper.
The flat sheet of paper experiences more air resistance because it has a larger surface area exposed to the air. Air resistance is a force that acts against the motion of an object. The crumpled paper has less air resistance, so gravity pulls it down more easily, causing it to fall faster.
Explain why it is important to keep constant variables the same in an experiment. How can changing a constant variable affect the results?
Keeping constant variables the same is crucial to ensure that any observed changes in the dependent variable are solely due to the independent variable, as altering a constant variable can introduce uncontrolled factors that skew the results.
A car is moving at a constant speed on a flat road. What are the two contact forces acting on the car?
Friction, Normal Force
A charged balloon is brought near a wall. Describe the process of electrostatic induction that occurs. What happens to the charges in both the balloon and the wall, and how does this lead to an attractive force between them?
When a charged balloon approaches the wall, it induces opposite charges on the wall's surface. The wall's positive charges move closer to the balloon, while negative charges are repelled. This separation of charges creates an attractive force between the balloon and the wall.
A car is accelerating to the right on a flat road. Draw a detailed force diagram showing all the forces acting on the car
Forces include friction, gravitational, push, normal force.
Newton's First Law of Motion: an object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
Explain how this relates to a person riding a bike at a consistent rate.
Varying answers
Design your own experiment and name the Independent, dependent and controlled variables in the experiment.
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