Science Forces Test

What is a force?

A force is a push or pull on an object resulting from its interaction with another object. 

What units are forces measured in?

N (Newtons)

 What are contact and non-contact forces, how do they compare, and what are examples of each?

Contact forces happen when two objects are physically touching, while non-contact forces act over a distance without physical touch.

• Contact Examples: Friction, air resistance, and tension.

• Non-Contact Examples: Gravity, magnetism, and static electricity.

How can you use arrows to represent forces on a diagram, and how do you interpret them?

 On a force diagram, the arrow's direction shows which way the force is pushing or pulling, and the length shows how strong the force is. If the opposite arrows are equal in length, the forces are balanced and the motion does not change. If one arrow is longer, the forces are unbalanced and the object will speed up, slow down, or change direction.

What is net force, and how do you calculate it?

Net force is the total overall force acting on an object after combining all individual forces. To calculate it, you add forces that are moving in the same direction and subtract forces that are moving in opposite directions.

What is gravity, and what determines how much gravity exists between two objects?

Gravity is an invisible force of attraction that pulls objects toward each other. The amount of gravity between two objects is determined by their mass (more mass equals stronger gravity) and the distance between them (closer objects experience stronger gravity).

Why is gravity different on other planets and moons?

Gravity is different because every planet and moon has a different mass and physical size. For example, the Moon has less mass than Earth, so its gravity is much weaker, while Jupiter has massive weight, creating a much stronger gravitational pull.

What is mass, what is weight, how are they different, and what units are used for each?

Mass is the amount of matter inside an object, it never changes based on location, and it is measured in kilograms (kg). Weight is the actual force of gravity pulling down on that mass, it changes depending on what planet you are standing on, and it is measured in Newtons (N).

 What is air resistance, and what effect does it have on moving objects?

Air resistance is a type of friction caused by air particles bumping into a moving object. Its effect is to slow down the moving object, and this force increases if the object moves faster or has a larger surface area.

What is air pressure, and how does it act on objects?

Air pressure is the force exerted by the weight of air particles pressing down on a surface. It acts equally in all directions at once, pushing inward on every exposed surface of an object.

What is friction, what effect does it have on moving objects, and how can it be reduced?

Friction is the resistance force created when two surfaces slide against each other, always acting in the opposite direction to slow things down. It is helpful for walking without slipping or using car brakes, but it is a hindrance when it causes engine parts to overheat or wear down. You can reduce friction by using lubricants (like oil), wheels, or streamlined shapes.

What is magnetic force, and what happens when you bring magnets near one another?

Magnetic force is a non-contact force created by electric charges that can pull or push objects over a distance. When brought close together, like poles repel each other (North-North or South-South push apart) and opposite poles attract each other (North-South snap together).

What are the three types of levers, and what are examples of each?

Levers are split into three classes depending on what sits in the middle:

• First-Class (Fulcrum in the middle): Seesaw, scissors, crowbar.

• Second-Class (Load in the middle): Wheelbarrow, nutcracker, bottle opener.

• Third-Class (Effort in the middle): Tweezers, fishing rod, human forearm.