Chemistry Unit Review



Name: Physics Unit Test Study Guide Date:

1. What is a frame of reference? Give examples.

An object that appears to stay in place compared to another object that is moving in front of it. Examples include: trees on the side of the road, a mountain, a group of people…

2. Identify the two factors that determine an object’s speed. How is speed calculated?

Distance travelled and time Speed = Distance/ Time

3. What is velocity? How is it different than speed?

Velocity is speed in a certain direction (includes a direction where speed does not)

4. How is acceleration calculated?

A = final velocity – initial velocity/ final time – initial time

5. Explain how to combine forces that occur in the same direction and in opposite directions.

Forces in the same direction are added together and forces in opposite directions are subtracted.

6. What can an unbalanced force do to an object’s motion?

Unbalanced forces can change the speed or direction of a moving object, start it moving, or stop it.

7. How can you determine if the forces on an object are balanced or unbalanced?

Forces are balanced on an object if the net force = zero (cancel each other out).

8. What is friction? What characteristics create a large or small amount of friction?

Friction is a force that opposed motion between surfaces in contact. Factors that affect the amount of friction include weight/ force pushing the surfaces together and the texture of the surfaces.

9. Define static friction and kinetic friction.

Static friction is between surfaces that are not moving and kinetic is between moving objects. Static keeps objects in place.

10. Name and define the 3 types of kinetic friction.

Sliding: surfaces slide over each other

Rolling: use of wheels or similar shapes for objects to move over each other

Fluid: movement of a surface with a gas or liquid

11. What are mass and weight? How are they different?

Mass is the amount of matter in an object where weight is the amount of gravitational force pulling it to earth

Mass is measured in kg and weight is measured in Newtons. Weight changes in space but mass does not.

12. Why do all objects fall at the same rate? What is this rate? Who determined this?

All objects are accelerated toward Earth at 9.8 m/s2 (it speeds up by 9.8 m/s every second). Galileo determined this to be true because heavier objects are pulled to earth with more force use up this extra force since it is more difficult to move a more massive object.

13. Which factors determine how much gravitational force there is between objects?

The amount of gravity between objects is affected by the mass of the objects and the distance between them.

14. What is projectile motion (what 2 types of motion must be taking place)?

Projectile motion is the curved path that an object takes. It must be moving both horizontally and vertically.

15. What forces act on falling objects? How do these forces affect how quickly an object falls?

Falling objects are affected by gravity (down) and air resistance (against the motion). Gravity causes objects to speed up as they fall to the ground and air resistance slows them down.

16. What is Newton’s First Law? Give an example.

Objects at rest stay at rest and objects in motion stay in motion…until an unbalanced force acts on them. You continue to move forward in the car when you slam on the brakes.

17. Define inertia. How does inertia relate to mass?

Inertia is the tendency of an object to resist a change in motion. Mass is a measure of inertia. The more mass an object has the harder it is to change its motion.

18. What is Newton’s Second Law? Give an example.

The acceleration of an object depends on its mass and the force applied to it. A full shopping cart is harder to accelerate than an empty one. A baseball hit by an adult goes faster than one hit by a child.

19. How does mass and force affect acceleration?

More mass means harder to accelerate. More force means more acceleration.

20. What is Newton’s Third Law? Give an example.

Every action has an equal and opposite reaction. A man in a canoe pushes the water back to make the canoe go forward.

21. What is momentum?

Momentum tells you how difficult it is to stop an object.

22. How can an object’s momentum be determined (calculated)?

Momentum = mass x velocity (units are kgm/s)

23. What does the Law of Conservation of Momentum say? Give an example of this law occurring.

The total momentum does not change as objects hit each other but instead is transferred. A bowling ball rolls down a lane and transfers some of its momentum to the pins to make them move. The total momentum between the ball and pins added up would be equal to that of the ball at the beginning.

24. Define work and explain how machines affect work.

Work is the use of force to move an object (W = F x D). Machines are able to make work easier by changing the force (changing the amount, distance, or direction).

25. Define mechanical advantage and how to calculate it.

Mechanical advantage = Output force/ input force (how much the machine is helping you)

26. Name and describe the 6 types of simple machines.

1. Inclined plane- sloping surface that connects a higher and lower elevation

2. Wedge- 2 inclined planes

3. Screw- inclined plane wrapped around a cylinder or cone

4. Lever- a bar that rotates around a fixed point called a fulcrum

5. Pulley- rope and grooved wheel

6. Wheel and axle- 2 connected rings or cylinder

27. Define compound machines and give an example.

A compound machine is made up of more than one simple machine. Examples include: scissors, bikes, fishing rods with reels…

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