Quarter 3 Science Review

Two identical basketballs in two different countries are dropped from the same height above the ground. Basketball 1 is located in North America in the Northern Hemisphere. Basketball 2 is located in Africa in the South Hemisphere. The illustration below shows the location of each basketball. What two statements are true about the gravity acting on Basketball 1 and Basketball 2?

• Earth's gravity causes the balls to fall away from each other

• Earth's gravity causes the balls to fall toward Earth's center.

• Earth's gravity causes Basketball 1 to fall towards Earth's surface and Basketball 2 to fall away from Earth's surface.

• The gravity acting on Basketball 1 points in the same direction as the gravity acting on Basketball 2.

• The gravity acting on Basketball 1 points to the same location as the gravity acting on Basketball 2.

Which of the following is the best example of Earth's gravity causing an object to move?

• smoke rising from a candle

• a girl walking to school

• a person pushing a shopping cart

• a ball rolling down a hill

Imagine a person standing on the surface of Earth at the equator as pictured below. The person is holding a ball and releases it. Which path best shows the direction of Earth's gravity acting on the ball?

• Path A

• Path B

• Path C

• Path D

An astronaut on the moon drops a hammer and a feather from the same height. The objects both hit the surface at the same time. Which of the following statements describes what is happening?

• The feather has less mass than the hammer, so the force of gravity on the feather is greater than the force of gravity on the hammer.

• The hammer has more mass than the feather, so the force of gravity on the hammer is greater than the force of gravity on the feather.

• Both objects hit the ground at the same time, so the force of gravity is equal for both of them.

• None of the above

Astronauts start floating in their spacecraft once they are far enough from the Earth's surface. Which statement correctly explains why astronauts start to float?

• Because their mass is too small for them to feel gravity.

• Because they are too far away from Earth to have any mass.

• Because they are so far away that gravity points away from Earth.

• Because the spacecraft and everything in it are all falling at the same rate around the Earth.

A person ties a ball to the end of a string. They swing the string above their head in a circle, which causes the ball to swing in a circular motion parallel to the ground. Which of the following pair of sentences do you think would best describe the SPEED and DIRECTION of the ball if the person lets go of the string?

• The ball's speed goes faster. The ball moves in a back-and-forth pattern.

• The ball's speed slows down. The ball moves in a back-and-forth pattern.

• The ball's speed stays the same. The ball continues to move in a circular pattern.

• The ball's speed stays the same. The ball flies off in one direction.

The diagram below shows water flowing on a waterwheel. The force of the water hitting each paddle on the wheel causes the waterwheel to rotate. Which change to this system would most likely make the waterwheel rotate faster?

• Place the water higher above the waterwheel.

• Increase the temperature of the water.

• Remove the paddles from the waterwheel.

• Use bottled water instead of tap water.

Which of the following is MOST important to consider when choosing the type of rope for the pulley system?

• the shape of the pulley bucket handle

• the speed at which the pulley wheel moves

• the amount of weight the pulley bucket will hold

• the distance of the pulley wheel from the platform

A company makes a prototype of a product. Workers in the company test the prototype before they make the final product. Which step will best help the workers when they test the prototype?

• Perform a test once and then make the final product.

• Make sure all the results show that the prototype has no flaws.

• Stop working on the product if the test shows a problem with the prototype.

• Use results of the test to improve the prototype before making the final product.

An engineering team realizes that they need to change their prototype of a rocket so that the body tube has a mass that is greater than the nose cone. Which of the following tools could they use to best gather this data?

• graduated cylinder

• balance scale

• microscope

• measuring tape