Name: _______________________________ Date: _________________ Hr:_______
Review: Newton’s First Law
Complete this review packet to the best of your ability using your notes, labs, and previous
worksheets. The amount of work you put into the review will reflect on your test. The review sheet
covers the main topics of the test- you should still study your notes and other worksheets.
Define the following terms and provide examples of proper units for each:
Speed- distance an object travels in a certain period of time (km/hr, yd/min, mi/hr, etc)
Velocity – speed with the direction of travel (km/hr, yd/min, mi/hr, etc)
Distance – space between point a and point b (km, mi, yd, m, etc)
Displacement - distance from starting point, includes direction (km, mi, yd, m, etc)
Force – push or a pull that causes a change in direction and/or speed (N- Newtons); weight is a
force!
Define the following terms and provide examples of each:
Vector Quantity- has a magnitude (#) and size (velocity, displacement, force)
Equilibrium Rule – states forces acting on an object must be equal and opposite if the object is
at rest OR moving with constant velocity (you can’t fall through the floor b/c the floor has a
support or normal force pushing up against the pull of gravity and your weight downward)
Inertia – laziness of objects
Newton’s 1st Law – law of inertia: things like to continue doing what they were doing (stay at
rest or remain in constant motion with constant speed and direction)
Frame of Reference – what you compare motion to (if you jump over a stick, your frame of
reference could be the stick which hasn’t moved, the ground which hasn’t moved, the trees
around you, etc)
Motion – occurs when object changes its position (like walking from RHS to TACO BELL!!!)
Net force – total overall force applied on an object (a book on a table has net force of 0 N since
all forces are equal and opposite)
Answer the questions below (you do NOT need to use complete sentences!)
1. What are 4 examples of everyday forces? What direction do these forces act?
Gravity- down
Support/Normal force- up
Friction- against motion
applied- direction of motion
2. What is the equation for speed? Time? Distance?
S = d/t
T = D/S
D = S*T
3. Explain the statement: Velocity is to speed as displacement is to distance.
Velocity is the vector quantity of speed (speed + direction = velocity) just like
displacement is the vector quantity of distance (distance + direction = displacement)
4. If an object is in motion, how do you know if it is in equilibrium?
Stays at constant speed in constant direction
5. What are balanced forces? Unbalanced forces?
B = Forces that are equal in size and opposite in direction
U = forces that are unequal in size and/or in same direction
6. What symbol is used to represent vector quantities? What information can that symbol tell us?
Arrows = direction of vector quantity and magnitude (larger arrow = bigger magnitude)
7. On a distance-time graph, what does the magnitude (steepness) of the slope tell you?
Speed! Steeper = faster
7. On a distance-time graph, what does the direction of the slope tell you?
What direction the object is traveling (upward slope = positive direction, downward
slope = negative direction)
8. Use Newton’s 1st law to explain why you lurch forward in a bus that suddenly slows and backward
in a bus that is picking up speed.
You have inertia forward when the bus is moving forward so you will continue to move
in that direction until stopped by an outside force. You want to stay in your same location
when the bus starts moving, so your body goes backward.
9. If you toss a coin straight upward while riding in a train, where does the coin land (relative to your
hand) when the motion of the train is along a straight line track? When the train slows while the
coin is in the air? When the train turns right?
a. in your hand (you, the train, the coin all have the same forward velocity and will
continue to have that velocity so you all travel the same distance while the coin is in
the air)
b. In front of you (you and the train have a slower horizontal velocity than the coin b/c
the coin is still moving at the original velocity and you have slowed down. The coin
travels farther than you do.)
c. To your left (you and the train turn right but the coin continues to travel in a straight
line forward, therefore lands to your left.)
10. If a person distributes their weight evenly among 2 scales, how would the reading of each scale
compare to their original weight?
½ of the original weight
Calculate: SHOW YOUR WORK (equation, plug in the numbers, and answer with units!)
1. A tennis ball travels the length of the court (24 m) in a total of 0.5 seconds. What is the average
speed of the ball?
S = d/t= 48 m/s
2. The earth travels at a speed of 100,000 km/hr. How many seconds would it take the earth to
travel 500 km?
T = d/s = 500 km/100,000 km/hr = 0.005 hr (use DA!) = 0.3 min
3. How long will it take light moving at 300,000 km/s to reach us from the sun? The sun is
15,000,000 km from earth
T = d/s = 15,000,000 km/300,000 km/s = 50 s (optional = 0.833 min)
4. The fastest train in the world moves at 500 km/hr. How far will it go in 45 min?
45 min (use DA) = 0.75 hr
D = t * s = 0.75 hr * 500 km/hr = 375 km
Graphs: Construct 2 graphs using the data given below. Use your graphs to answer the
questions for each data set.
Distance (m)
10
20
35
65
85
100
Time (sec)
20
40
70
130
170
200
1. Does this graph represent constant or changing speed? How do
you know?
Constant- slope of the line is straight (consistent)
2. What is the average speed of the object?
S = total d/total t = 100 m / 200 sec = 0.5 m/sec
Distance (m)
15
25
40
70
90
100
Time (sec)
20
50
65
130
185
200
3. Does this graph represent constant or changing speed? How do
you know?
Changing- line does not have a constant slope!
4. Which section of the graph represents the highest speed? How do you know?
Time 50 until time 65 seconds, Steepest slope
5. What is the speed from time 130 to 185 s? What is the average speed of the object?
S = d/t = (90 – 70 m)/(185 – 130 s) = 20 m/55 s = 0.36 m/sec
S = total d/ total t = 100 m / 200 sec = 0.5 m/sec
6. On a distance time graph, how can you tell if an object is at rest?
Horizontal line (no distance covered so no speed!)