8th Grade Midterm

You are pulling a wagon across the grass.  The grass gives a frictional force of 15N opposite the motion.  If the wagon is moving with a constant momentum, what is your pulling force? 

• 30N
• 0N
• Cannot be determined.
• 15N

As the mass of an object increases, the force of gravity 

• decreases
• increases
• stays the same
• may increase or decrease depending on the objec's distance from Earth

How is the acceleration due to gravity experienced by a satellite affected if  the mass of the satellite decreased by half?

• The acceleration increases.
• The acceleration remains the same.
• The acceleration decreases. 
• The acceleration results in a chance in direction. 

Action and reaction forces

• always act on different objects
• always act on the same object
• cancel each other out
• can act on the same or different objects depending on the situation 

This is a type of energy that is a result of friction

• inertia
• heat
• electric
• chemical

Mrs. Yuska would like to conduct an experiment  to investigate whether or not drinking too much hot chocolate causes one to turn into an elf .  If she is using the Scientific Method, what step should she take first?

• Design and experiment that test the effects of hot chocolate on various 8th graders.
• Observe various 8th graders drinking hot chocolate.
• Conduct research to obtain any information that already exists on this topic. 
• Cancel class and order a box of hot chocolate from Dunkin Donuts. 

Which of the following will change an object's momentum?

• change in its electrical charge
• change in its mass
• change in its sound
• change in its color

Which physical law most directly describes the motions of objects that are acted on by forces?

• Newton's First Law
• Newton's Second Law
• Newton's Law of Universal Gravitation
• Newton's Third Law

Sliding friction makes objects easier to move than rolling friction does. 

• True
• False

Which is true about gravity?

• It is a force that causes all objects to repel each other. 
• The mass of an object determines the amount of gravitational pull on it. 
• Mass is determined by gravity. 
• The more mass an object had the less the gravitation force it has.