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Questions and Answers
A book rests on a table. Which of the following best describes the forces acting on the book?
A book rests on a table. Which of the following best describes the forces acting on the book?
- Only gravity, as the table is not actively pushing the book.
- Gravity pulling the book downwards and friction acting horizontally against any potential movement.
- Gravity pulling the book downwards and a contact force from the table pushing upwards, resulting in a net force of zero. (correct)
- Only the contact force from the table, as gravity is negligible at this scale.
Which of the following scenarios involves static friction?
Which of the following scenarios involves static friction?
- A hockey puck sliding across an ice rink.
- A car's tires rolling without slipping on the road. (correct)
- An object moving through water.
- A box being pushed across a rough floor and moving at a constant speed.
An astronaut has a mass of 70kg on Earth. Which statement is true when the astronaut is on the Moon?
An astronaut has a mass of 70kg on Earth. Which statement is true when the astronaut is on the Moon?
- The astronaut's mass and weight will be the same as on Earth.
- The astronaut's mass will be less, but their weight will remain the same.
- The astronaut's mass will remain the same, but their weight will be less. (correct)
- Both the astronaut's mass and weight will be less than on Earth.
A student pushes a box across a floor with a force of 50N. The force of sliding friction acting on the box is 20N. What is the net force acting on the box?
A student pushes a box across a floor with a force of 50N. The force of sliding friction acting on the box is 20N. What is the net force acting on the box?
Which of the following is an example of a non-contact force?
Which of the following is an example of a non-contact force?
How does increasing the distance between two objects affect the gravitational force between them?
How does increasing the distance between two objects affect the gravitational force between them?
Which of the following is the best example of fluid friction?
Which of the following is the best example of fluid friction?
Two objects, one with a mass of 5kg and another with a mass of 10kg, are separated by a certain distance. How does the gravitational force exerted by the 10kg object on the 5kg object compare to the gravitational force exerted by the 5kg object on the 10kg object?
Two objects, one with a mass of 5kg and another with a mass of 10kg, are separated by a certain distance. How does the gravitational force exerted by the 10kg object on the 5kg object compare to the gravitational force exerted by the 5kg object on the 10kg object?
Flashcards
Force
Force
A push or pull on an object, measured in newtons (N).
Contact Force
Contact Force
A force that requires direct contact between objects.
Non-Contact Force
Non-Contact Force
A force that acts between objects without direct contact.
Friction
Friction
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Static Friction
Static Friction
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Sliding Friction
Sliding Friction
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Fluid Friction
Fluid Friction
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Gravity
Gravity
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Study Notes
- Forces change the motion of an object.
Gravity and Friction
- Contact forces and non-contact forces need to be considered.
- Universal gravitation is a key concept.
- Friction impacts the motion of objects sliding.
Types of Forces
- A force is a push or pull on an object
- Forces are measured in newtons (N).
- Contact forces involve touching.
- Pushing a container, pressing on computer keys and friction are examples of contact force.
- Non-contact forces do not involve touching.
- Gravity, magnetic and electrical forces are examples of non-contact force.
Types of Friction
- Friction resists motion between touching objects.
- Static friction prevents objects from sliding.
- Sliding friction opposes the motion of sliding objects.
- Fluid friction occurs between a surface and a fluid like water or air, also known as air resistance.
Static Friction vs. Sliding Friction
- In Static Friction, a static friction of -100N and an applied force of 100N results in Net Force of 0N.
- In Sliding Friction, with sliding friction of -70N and applied force of 200N results in Net Force.
Gravity
- Gravity is an attractive force between objects with mass.
- Mass is the amount of matter in an object.
- Greater mass means more gravitational pull.
- Greater distance means less gravitational pull.
Weight vs. Mass
- An astronaut weighs 539N and has a mass of 55kg on Earth
- On the moon, her weight would be less.
- Her mass will not change unless she became thinner or fatter.
Non-contact Electrical Force
- Static charge refers to unbalanced positive or negative charge on an object.
- Opposite charges attract.
- Similar charges repel.
- More charge equals greater electrical force (attraction or repulsion).
- More distance equals less electrical force.
Non-contact Magnetic Force
- Magnet is an object that attracts metal iron
- Magnetic pole is the location on a magnet where the force is the strongest
- Opposite poles attract.
- Similar poles repel.
- Magnetic strength depends on size of magnet.
- Magnetic force weakens with distance.
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Description
Explore forces including gravity, friction, contact, and non-contact forces. Learn about universal gravitation and how friction affects motion. Understand static, sliding, and fluid friction and is measured in newtons (N).
