Friction
Gravity
Mixed
100
Friction
What is the force that opposes motion between to surfaces that touch?
100

Give one way to overcome gravity

Use of aerofoil wings, using of jet engines, rotors or propellers

100

Gravitational Force/ Gravity

What pulls objects toward each other?

200

What is the opposing force between wheels and the floor?

Rolling Friction

200

It is still the same even you are outside the universe?

Mass

200

Who developed the Law of Universal Gravitation?

Sir Isaac Newton

300

What creates more friction?

rough surfaces, greater mass, greater surface area, 

300

Give at least two scientist who studied about gravity, or paved the way for it to be discovered?

Isaac Newton, Albert Einstein, Nicholas Copernicus, Johannes Kepler, Galileo Galilei

300

Who developed the "Law of Gravitation"?

Isaac Newton

400

Why does a crumpled piece of paper land back before a flat sheet of paper?

There is more air resistance on the flat paper.

400

It changes when gravitational force changes.

Weight

400

Why does a flat sheet of paper falls slowly than a crumpled piece of paper?

There is more air resistance on the flat paper.

500

Give at least 2 ways to decrease friction.

Use smooth surfaces, wheels, grease, oil, lubricant, reduce weight, streamlining

500

How are tides formed?

Through the attraction between water on earth and moon's gravity.

500

What will be the weight of a man who is 70 kg in outer space?

Zero