Grade 8 diagnostic test

Which would best increase the magnetism (磁性) of a temporary magnet?

• Use a larger battery.

• reduce the turns of the coil used.

• Use an insulator instead of wire.

• Increase the temperature.

Brock Heart's action was pushing his feet on the wall of a pool. The reaction was an equal and opposite force that was placed upon him from the wall pushing him

forward. This is an example of ___________.

• Newton's First Law

• Newton's Second Law

• Newton's Third Law

• Boyle's Law

Which best describes the reason why the planets in our solar system orbit the Sun?

• Only the planets have pull of gravity on the Sun.

• The Sun's pull of gravity on the planets.

• The Sun's gravity pushing on all the planets.

• The gravity of all the planets pushing away from the Sun.

A lunar eclipse occurs when _________

• The moon is between the Earth and Sun.

• There are neap tides on Earth.

• The Earth is closest to Mars.

• The Earth is between the Sun and moon.

The Earth’s moon continues to orbit the Earth due to ___________ .

• Earth's lower amount of mass

• Earth's gravity pulling on the moon

• Earth's atmosphere

• Earth's gravity pushing on the moon

Which is the best example of Newton's Third Law?

• When children increase their speed, they also increase their force.

• A child traveling down a slide will continue to travel until forces cause his or her to stop.

• When a child applies a strong enough force to the ground, the ground applies a force back on the child allowing his or her to jump in the air.

• A child is pushing a cart. If the child decreases his or her force on the cart, the cart will slow down.

An object composed mainly of ice is orbiting the Sun in an elliptical path (椭圆). This object is most likely

• a planet

• an asteroid

• a meteor

• a comet

Which of the following is the best example of two non-contact forces (不接触的力) acting on each other?

• Heating an iron pan on a hot stove.

• Two magnets of same charge pushing away from each other.

• A man pushing on a wall and the wall is not moving.

• A ball bouncing off the ground.

Which of the following has the most elliptical orbit (最椭圆的) around the Sun?

• planets

• comets

• asteroids

• moons

Based on the magnetic field line diagrams, what will happen next with these two sets of magnets?

• The magnets in Set 1 will repel, and the magnets in Set 2 will attract.

• The magnets in Set 1 will attract, and the magnets in Set 2 will repel.

• The magnets in Set 1 will not move, and the magnets in Set 2 will attract.

• In both sets, the magnets will attract.