Answer:
b friction
Explanation:
Contact forces
Contact forces are forces that act between two objects that are physically touching each other. Examples of contact forces include:
Reaction force
An object at rest on a surface experiences reaction force. For example, a book on a table.
A box rests on a table. There are two arrows, equal in size but going in opposite directions, up and down, from the point where the box meets the table.
Tension
An object that is being stretched experiences a tension force. For example, a cable holding a ceiling lamp.
A box hangs from a rope. Two arrows which are equal in size act upwards and dowards from the top and bottom of the rope.
Friction
Two objects sliding past each other experience friction forces. For example, a box sliding down a slope.
A box rests on an incline. There are three arrows; one acting vertically downwards from the centre of the box’s base. One arrow acts perpendicular to the incline. One arrow acts up the incline.
Air resistance
An object moving through the air experiences air resistance. For example, a skydiver falling through the air.
A box falls from the sky. Two arrows, equal in size and opposite in direction act upwards from the box and downwards from the box
When a contact force acts between two objects, both objects experience the same size force, but in opposite directions. This is Newton's Third Law of Motion.
Answer:
gas, liquid, solid
sound cannot travel in space
Answer:
A.) the inverse of the square of the distance separating them
Explanation:
Coulombs law states that "the force of attraction between two charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them."
Mathematically, F = kq1q2/r²
Where q1 and q2 are the charges
r is the distance between the charges.
According to the law, the force between two charged objects is related to the inverse of the square of the distance separating them.
Answer:
As the skydiver falls to the Earth, she experiences positive acceleration only due to gravity.
Explanation:
As the skydiver falls to the Earth, she experiences friction in the form of air resistance which tries to slow her down and is proportional to the her velocity. So it cannot have a positive acceleration as it acts in opposite direction to slow her down.
Inertia during skydiving is experienced when we open an parachute, the parachute slows down the speed of are descent hence changing our inertia of motion with a velocity.
Only the Earth's, gravitational field has an positive acceleration as it pulls us towards the Earth, hence increasing our velocity.
