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Using the five problem-solving steps, solve the following problems on your own. Be sure to read the
problem carefully. Show your work in the blank provided.
Step
9,
I
What quantity or rate are you asked for in the problem? Write it down.
Step 2
What do you know from reading the problem? List all known rates and quantities.
Step
Arrange the known quantities and rates to get an answer that has the right units. Thls
arrangement might include a formula.
3
Step 4
Plug in the values you know.
Step
Solve the problem and write the answer with a number and a unit.
5
How much willyou pay for 5 pounds of shrimp if the cost is 2 pounds for $10.99?
10. How many miles can you get on one tank of gas if your tank holds l8 gallons and you get22 miles per
gallon?
1
I
.
What is your rate in miles/hour if you run at a speed of 2.2 miles in 20 minutes?
12. Suppose for your cookout you need to make
100 hamburgers. You know that 2.00 pounds
will make
t hamburgers. How many pounds willyou need?
13. What is your mass in kilograms if you weigh 120 pounds? (There are approximately 2.2 pounds in one
kilogram.)
14. Mt. Everest is29,028 feet high. How many miles is this? (There arc 5,280 feet in one mile.)
15. Susan works 8 hours
a day and makes $7.00 per hour. How much money does Susan earn in one week
if
she
works 5 days per week?
16. How many years will it take a major hamburger fast food chain to sell 45,000,000 burgers if it sells
approximately 12,350 burgers per day?
17. Your science teacher needs to make more of a salt-water mixture. The concentration of the mixture that
needed is 35 grams of salt in 1,000 milliliters of water. How many grams of salt willbe needed to make
1,500 milliliters of the salt-water?
is
18. A cart travels down a ramp at an average speed of 5.00 centimeters/second. What is the speed of the cart in
miles/hour? (Remember there are 100 centimeters per meter, 1000 meters/kilometer" and 1.6 kilometer per
mile.)
19. A person goes to the doctor and will need a 3-month prescription of medicine. The person will be required to
take 3 pills per day. How many pills will the doctor write the prescription for assuming there are 30 days in a
month?
20. If you are travelin g at 65 miles per hour, how many feet will you
be
traveling in one second?
Name:
Date:
Acceleration Problems
READ
ffi
Acceleration is the rate of change in the speed of an object. To detennine the rate of acceleration, you use the
formula below. The units for acceleration are meters per second per second or m/sec2.
Acceleration
_
Final speed
Beginning speed
Time
-
, - v2-vl
A positive value foracceleration refers to the rate of speeding up, and negative value foracceleration refers
to the rate of slowing down. The rate of slowing down is also called deceleration.
The acceleration formula can be rearranged to solve for other variables such as final speed
(v)
andtime (r).
v2= vt+@xt)
^zt
y"-v,
q
Et(AluprEs
El
A skater increases her velocity from 2.0 m/sec to 10.0 m/sec in 3.0 seconds. What is the skater's
acceleration?
Looking for
Solution
Acceleration of the skater
Given
Beginning speed :2.0
Final speed :
Acceleration =
mlsec
10.0 m/sec
Change in time
:
3 seconds
Relationship
a:-
10.0
vt-vr
t
m
2.0 m
3 sec
8.0 m
=
*2.7m
-g_
3 sec s""'
The acceleration of the skater is 2.7 meters per
second per second.
Page 2 of 3
r
car accelerates at a rate of 3.0 rn/sec2. If its original speed is 8.0 rn/sec, how many seconds
take the car to reach a final speed of 25.0 m/sec?
d
will it
Solution
Looking for
The tirne to reach the final speed.
Time
Given
25.0 m/sec
-
8.0 m/sec
3.0 m/sec2
Beginning speed: 8.0 m/sec
Final speed
:
Acceleration
Time
25.0 m/sec
:
17.0 m/seg
:
5.7 sec
3.0 m/sec-
3.0 m/sec2
The time for the car to reach its is 5.7 seconds.
Relationship
v2-vl
a
FRAGTICE
I
.
p>-*--
While traveling along a highway a driver slows from 24 m/sec to l5 m/sec in l2 seconds. What is the
automobile's acceleration? (Remember that a negative value indicates a slowing down or deceleration.)
Looking for
Solution
Given
Relationship
2.
A parachute on a racing dragster opens and changes the speed of the car from 85 m/sec to 45 rn/sec in a
period of 4.5 seconds. What is the acceleration of the dragster?
a
J.
4.
5.
The cheetah, which is the fastest land mammal, can accelerate from 0.0 mi/hr to 70.0 mi/hr in 3.0 seconds.
What is the acceleration of the cheetah? Give your answer in units of mph/sec'
The Lamborghini Diablo sports car can accelerate from 0.0 km/hr to 99.2 km/hr in 4.0 seconds. What is the
acceleration of this car? Give your answer in units of kilorneters per hour/sec.
Which has greater acceleration, the cheetah or the Lamborghini Diablo? (To figure this out, you must
remember that there are 1.6 kilometers in 1 mile.) Be sure to show your calculations.
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6.
The table below includes data for a ball rolling down a hill.
and determine the acceleration of the rolling ball.
7.
A car traveling at a speed of 30.0 m/sec encounters an emergency and comes to a complete stop. How much
time will it take for the car to stop if its rate of deceleration is -4.0 mlsecz?
8.
If a car can go from 0.0 to 60.0 miihr in 8.0 seconds. what would be its final speed after 5.0 seconds if its
Fill in the missing data values in the table
starting speed were 50.0 mi/hr?
9.
A cart rolling down an incline for 5.0 seconds has an acceleration of 4.0 mlsec2.lf the cart has a beginning
speed of 2.0 m/sec, what is its final speed?
t0. A helicopter's speed increases from 25 m/sec to 60 m/sec in 5 seconds. What is the acceleration of this
helicopter?
ll.
Below are three situations. In which is the acceleration most similar to the helicopters in question l0?
a.
b.
c.
An object going from 0 m/sec to 25 m/sec in 5 seconds.
An object going from 0 m/sec to 7 m/sec in 2 seconds.
An object going from 5 km/h to 30 km/h in I second.
Name:
Date:
Applying Newton's Laws of Motion
READ
ffi
In the second column of the table below, write each of NeMon's three laws of motion. Use your own word[ng. In
the third column of the table, describe an example of each law. To find examples of Newton's laws, think about
all the activities you do in one day.
The first law
The third law
PRACTICFfu<*^
l.
When Jane drives to work, she always places her purse on the passenger's seat. By the time she gets to work,
her purse has fallen on the floor in front of the passenger seat. One day, she asks you to explain why this
happens in terms of physics. What do you say?
2.
You are waiting in line to use the diving board at your local pool. While watching people dive into the pool
from the board, you realize that using a diving board to spring into the air before a dive is a good example of
Newton's third law of motion. Explain how a diving board illustrates Newton's third law of motion.
3.
You know the mass of an object and the force applied to the object to make it move. Which of Newton's laws
of motion will help you calculate the acceleration of the object?
4.
How many newtons of force are represented by the following amount: 3 kg.m/sec2 ?
Select the correct answer (a, b, or c) and justify your answer.
a. 6 newtons
b. 3 newtons
c. I newton
5.
Your shopping cart has a mass of 65 kilograms. In order to accelerate the shoppin g cart down an aisle at
0.3 m/sec2, what force would you need to use or apply to the cart?
6.
A smallchild has a wagon with
a mass
of l0 kilograms. The child pulls on the wagon with
a force
of
2 newtons. What is the acceleration of the wagon?
7.
You dribble a basketball while walking on a basketball court. List and describe the pairs of action-reaction
forces in this situation.