EMM TEST REVIEW QUESTIONS Answer Key

  1. Define “Force”, then give an example of the following forces acting on objects in nature: Friction, Elastic, Gravitational, and Normal

A push or pull on an object. Can be both a contact or a non-contact force. Friction opposes motion (tires), elastic can store potential energy (rubber bands) Gravity is a non contact force and the Normal force is a perpendicular force of a surface.

  1. Define “Energy” then l list the 6 forms of energy we observed in labs this year.

The ability to do work or to change an object’s potential. Work, Kinetic, Thermal, Electrical, Chemical, and potential (gravitational and spring/elastic)

  1. Draw and label the essential parts of a wet cell and a dry cell battery.
  1. List the energy TRANSFORMATIONS as a battery operates a flashlight.

Chemical into electrical into thermal, into light (electromagnetic)

  1. List the energy TRANSFERS as a battery operates a flashlight.

Kinetic of the electrons in solution to the electrons in the wire

  1. What did you learn in Inq. 2: Making a Battery?

This should be a summary of their learning

  1. List the effects of increasing mass, surface roughness, and surface area on friction.

Mass increases friction as the normal force must increase, different surfaces affects friction, and surface area and speed do not affect surface friction.

  1. List 1 example of when friction is GOOD and how we want to increase it.

Friction for shoes and tires! Change surfaces or increase mass.

  1. List 1 example of when friction is BAD and how we want to decrease it.

Friction in motors decreases the ability of the motor to do it’s work so we change surface contact by using oils to lubricate items that rub.

  1. List the advantages of wiring batteries in series?

Increase the battery’s ability to lift or produce light.

  1. List the advantages of wiring batteries in parallel?

Increase the battery’s ability to last longer

  1. List an advantage and a disadvantage of using a large motor spindle instead of a small motor spindle.

Large spindle can lift rapidly but not lift as much weight as the small spindle

  1. Describe a situation where work is done, and where work is not done.

Holding a book has no work done while pushing it or lifting it does have work done on it.

  1. How much work is done lifting a 25 N block 5 meters? Include formula, work, and units.

W = FD, 25N ·5m = 125Nm = 125J

  1. Draw and label a force diagram showing at least 4 different forces working on an electric car moving across your table. Include arrows to indicate the direction of the forces. Use an arrow to show net force in addition to the other forces.
  1. List what would happen to the motion of a hockey puck if you hit it with a single sudden force and there was no friction on the puck.

The puck would quickly pick up speed (accelerate) and then continue at a constant speed

  1. List what would happen to a hockey puck if you applied a constant force to the hockey puck if there were no friction on the puck.

The puck would pick up speed (accelerate) as long as you still pushed it

  1. Find the average speed of the following a rabbit running 20 meters in 4.2 seconds.

Speed = d/t, 20m/4.2s = 4.8m/s

  1. List the definition of potential energy? Or give and example.

Stored energy like in a set mousetrap or a car at the top of a hill

  1. List the definition of kinetic energy? Or give an example.

Energy of a moving item, so anything that has mass and is moving like a moving train, a runner

  1. Write the formula for determining the gravitational potential energy.

W = FD, so gravitational potential energy is weight (force) times height (distance) = mgh

  1. Find the gravitational potential of an object that weighs 13 N and is 2.45 meters above the ground.

GPE= Weight · height, 13N · 2.45m = 32Nm = 32J

  1. What forces affect potential energy?

Friction? Mass or weight of an object, the height it’s raised or how far the spring is stretched, and gravity.

  1. What forces affect kinetic energy?

Friction? Mass or weight of an object and the speed it travels