PHYSCI ETA

Galileo's discovery that contradicted the Ptolemaic model?

The moons of Jupiter orbiting around Jupiter instead of Earth.

According to Kepler’s Third Law, what happens to planets farther from the Sun?

They have longer orbital periods.

What do objects in free-fall motion near Earth experience?

Constant acceleration of approximately 9.8 m/s².

What happens when a star attempts to fuse elements heavier than iron?

It collapses and triggers a supernova.

What did Eratosthenes use to determine that the Earth was spherical?

The difference in shadow angles at different locations.

Plato's problem of 'Saving the Appearances' in Greek astronomy?

Explaining planetary motion while preserving the idea of perfect circular orbits.

When a ball is thrown straight upward, what is its velocity at the highest point?

Zero.

What causes a bicycle to slow down when brakes are applied?

Friction between the tires and the road.

How does a catalyst work?

By lowering activation energy.

Why must a chemical equation be balanced?

To ensure the conservation of mass.

What happens to a car's kinetic energy when its speed doubles?

It quadruples.

What happens in an inelastic collision between two vehicles?

They stay joined together after impact.

What observation by Galileo weakened the geocentric model?

Venus’ phases similar to the Moon.

How did JJ Thomson contribute to atomic theory?

By identifying the electron.

How did Ptolemy explain retrograde motion?

By introducing epicycles.

What determines the atomic number of an element?

Its number of protons.

Why can't nuclear fusion occur naturally beyond iron?

Fusion past iron requires more energy than it releases.

CO₂ is classified as what type of molecule?

Nonpolar.

What happens when intermolecular forces weaken?

Liquids evaporate more quickly.

What results from stronger intermolecular forces?

Higher boiling points.

In projectile motion, how are the horizontal and vertical components of motion related?

They are independent of each other.

What principle explains why satellites remain in orbit?

Newton’s First Law – objects in motion stay in motion unless acted upon by an external force.

Changing which subatomic particle transforms one element into another?

Protons.

If an atom has 15 protons and a mass of 31, how many neutrons does it have?

16.

When do London dispersion forces occur?

Temporary dipoles arise in nonpolar molecules.

What occurs if an astronaut drops a hammer and a feather on the Moon?

Both hit the ground at the same time due to the absence of air resistance.

What determines molecular polarity?

The shape and electron distribution.

How is momentum best described?

It is the product of an object’s mass and velocity.

What observational evidence supports the Big Bang theory?

The abundance of hydrogen and helium.

According to Newton’s Second Law of Motion, what happens if the net force is doubled?

It doubles the acceleration.

How does a rocket move forward in space?

By expelling gas backward, creating an equal and opposite reaction.

What experiment led to the discovery of the atomic nucleus?

Rutherford’s gold foil experiment.

Why do astronauts appear weightless in the ISS?

They are in free fall, constantly falling toward Earth while moving forward.

Why does nuclear fusion occur in stars?

High temperatures and pressures force nuclei to combine.

Which molecule exhibits the strongest intermolecular forces?

H₂O.

What does the limiting reactant in a chemical reaction determine?

The maximum product yield.

What is an example of a chemical change?

Rust forming on iron.

What effect does raising temperature in a reaction generally have?

Increases collision frequency and reaction rate.

What process formed the first elements in the universe?

Primordial nucleosynthesis.

When is total mechanical energy conserved?

Only conservative forces (such as gravity) are acting.

What happens to gravitational force if distance is tripled?

It becomes 1/9 of the original force.

Where do most elements heavier than iron originate from?

Supernova explosions.

What type of reaction releases more energy than it absorbs?

Exothermic.

Which of Kepler’s Laws relates to planets traveling faster when closer to the Sun?

Kepler’s Second Law (Law of Equal Areas).

How does a car's crumple zone increase passenger safety?

Increases the time over which the impact occurs, reducing force.