Physics 504 - Midyear Review (Answers)

A

B

B

A

A

D

At time t = 200 s, the ski lift is closer to the bottom by 40 m.

The ball travels 14 m along the flat surface.

A

A

B

The time it takes the ball to hit the ground from the instant it is released is 2.16 s.

B

C

B

D

The two vehicles are 25 m apart after 30 seconds.

B

C

D

C

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D

B

The distance both vehicles had travelled is 500 m.

B

A

Aeron will run 22.5 m before she catches up with Cynthia.

B

The keys were in the air for 2.1 s.

The equilibrium force is 37 N [N20°W] or 37 N [W70°N]

B

A

A

D

Ali's acceleration at 400 seconds is 0 m/s2.

Ali's acceleration at 1200 seconds is -8.3 102 m/s2.

Ali's displacement between 800 seconds and 1400 seconds is 3.00 103m.

D

C

D

A

B

Malfoy will be first to reach the snitch with 1.2 s to spare!

The distance between the two cities is 1.21 103 km.

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Physics 504

Midyear Review

A cyclist is training for the Montreal Tour de l'Ile. She cycles from home to a provincial park, 80.0 km away in

2½ hours. After a short 15-minute rest, she makes the return trip, taking 31/4 hours.

What was her average speed for the full training session?

A) 26.7 km/h

B) 27.1 km/h

C) 27.8 km/h

D) 28.3 km/h

A roller coaster car, travelling with an initial velocity v , accelerates down a 12.0 m incline at a rate of 4.0 m/s2.

The car is moving at 10.0 m/s when it reaches the bottom of the hill.

v = ?

12 m

10 m/s

What is the magnitude of the car's initial velocity v as it starts down the incline?

A) 0.0 m/s

B) 2.0 m/s

C) 4.0 m/s

D) 6.0 m/s

1

2

A juggler tosses the last ball of his act up to a height of 3.0 m from the ground. He releases the ball from his

hand when it is 1.0 m above the ground. He misses catching it.

With what velocity does the ball strike the ground?

A)

4.4 m/s

B) 7.7 m/s

C) 9.9 m/s

D) 29 m/s

Ground

3.0 m

1.0 m

3

A customer in a grocery store picks up a can from a display and places it in his cart. After following the

path indicated in the diagram below, the can is placed on another shelf elsewhere in the store.

(Not drawn to scale).

Overhead View of Floor Plan of a Grocery Store

2.4 m

4.7 m

50 cm

Cart Can

Can

50 cm

(Initial position)

What is the magnitude of the displacement of the can from its original display location?

A) 4.6 m

C)

6.0 m

B)

5.3 m

D)

8.1 m

4

A cart rolls on a frictionless surface according to the diagram.

Which of the following is the correct choice for the corresponding distance-time and speed-time

graphs?

A)

time time

speed distance

B)

time time

speeddistance

C)

time time

speeddistance

D)

time time

speeddistance

6

A small, very dense sphere is in freefall toward the ground.

Which of the following variables is directly proportional to the elapsed time?

A) The distance it covers from the start

B) The position from the start

C) The acceleration at every instant

D) The speed at every instant

A ski lift moves up and down along a hill

according to the following V-t graph.

Unfortunately, it stalls on the way down at t =

200 s.

At this point, the rescue team must decide

whether the skiers are closer to the top or the

bottom of the hill.

Using the V-t graph, determine whether the ski

lift is closer to the top or to the bottom of the

hill and by how much.

Top

Bottom

Ski Lift

Ski Lift Velocity Graph

Velocity (m/s) 10

8

6

4

2

0

-2

-4

-8

-6

-10

20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 0

Time (s)

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8

From rest, a ball rolls down a 1.0 m long hill accelerating at a rate of 4.0 m/s2. It then continues

smoothly at a constant speed over a flat surface for 5.0 seconds. Ignore the effects of friction.

a = 4.0 m/s2

V1 = 0 m/s

1.0 m

?

5.0 seconds How far does the ball travel along the flat surface?

Which of the following situations will produce the displacement with the greatest magnitude?

A) 10 km 10 km

C)

10 km

10 km

B)

10 km

10 km

D)

10 km 10 km

The graphs below describe the motions of four different cars starting from rest.

Which car is travelling the fastest at 25 seconds?

A)

Time (s) 25

Acceleration

(m/s2)

2

Car A

C)

Time (s) 25

Position (m)

Car C

750

B)

Time (s) 25

Position (m)

Car B

600

D)

Time (s) 25

Velocity (m/s)

Car D

25

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The graph below shows the change of position of a cart through a 15 second interval.

What was the average acceleration of the cart from the 3rd to the 10th second?

Position (m)

Time (s)

10

20

30

40

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

50

60

70

80

90

100

A)

0.60 m/s2

C)

4.3 m/s2

B)

2.6 m/s2

D)

11 m/s2

A student conducts a free-fall experiment while standing on the edge of the school roof 12.0 m above the

ground. The student throws a heavy ball vertically upwards at a velocity of 5.00 m/s. On its way down, the ball

narrowly misses the roof and hits the ground.

How long does it take the ball to hit the ground from the instant it is released?

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In a map-reading exercise several students were given the following directions: From your starting point walk

4.00 km North, then 11.3 km 45° South of East, S45°E, and finally 8.00 km West. This is illustrated in the

vector diagram below.

4.00 km 11.3 km

8.00 km

North

What was the students’ displacement for this trip?

A) 4.00 km North

C)

23.3 km North

B) 4.00 km South D) 23.3 km South

Which of the following graphs illustrate non-uniform motion?

d

t

2 d

t

1

t

4 v

t

3 v

A)

Graphs 1 and 2

C)

Graphs 2 and 4

B)

Graphs 1 and 3

D)

Graphs 3 and 4

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The following velocity-time graph represents the motion of a panoramic elevator as it makes its way up from

the main floor to the top floor of an observation tower.

Velocity (m/s)

Time (s) 1 2 3 4 5 6

15

10

5

Which of the graphs below represents the acceleration of this elevator as it makes its way up to the top of the

tower?

A) Acceleration

Time (s)

0

B)

0

Acceleration

Time (s)

C)

0

Acceleration

Time (s)

D)

0

Acceleration

Time (s)

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The gravitational pull of Mars is approximately 10

4 the gravitational pull of Earth.

Which of the following velocity-time graphs represents the motion of a falling object on Mars?

A)

9.8

v(m/s)

t(s)

C)

100

v(m/s)

t(s) 10

B)

3.9

v(m/s)

t(s)

D)

109

v(m/s)

t(s) 28

A car and a truck leave a traffic light at the same time, travelling in the same direction. The graphs below

illustrate their motions.

15

10

5

10 20 30

Velocity (m/s)

Speed as a Function of Time

Car

Time (s)

300

200

100

10 20 30

Position (m)

Truck

Time (s)

Position as a Function of Time

How many metres apart are the two vehicles after 30 seconds?

Show all your work.

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Which of the following statements best defines uniform motion?

A)

Motion with constant speed

B)

Motion with constant velocity

C)

Motion with constant acceleration

D)

Motion with constant acceleration and constant direction

Veronica and Andreas studied the motion of four objects over a 10 second period. The velocity-time graph of

each object is presented below.

Which object covered the greatest distance during the 10 s period?

A)

-6

-4

-2

0

2

4

6

0 2 4 6 8 10

Time (s)

Velo

cit

y (

m/s

)

C)

-6

-4

-2

0

2

4

6

0 2 4 6 8 10

Time (s)

Velo

cit

y (

m/s

)

B)

-6

-4

-2

0

2

4

6

0 2 4 6 8 10

Time (s)

Velo

cit

y (

m/s

)

D)

0

1

2

3

4

5

6

0 2 4 6 8 10

Time (s)

Velo

cit

y (

m/s

)

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21

An object starting from rest is uniformly accelerated for 20 seconds and reaches a velocity of 20 m/s. It

travels at this velocity for 60 s and is brought to rest in 10 seconds by a constant deceleration.

1.

20

80 90

a (m/s2)

T (s)

2.

20

80 90

V (m/s)

T (s) 20

3.

a (m/s2)

T (s) 20

80 90

4. V (m/s)

T (s)

20

80 90 20

Which graphs best represent this situation?

A) Graphs 1 and 2

C)

Graphs 3 and 4

B) Graphs 2 and 3 D) Graphs 1 and 4

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Fred is sitting on a train that is moving out of the station. To pass the time, he holds his keys with an

outstretched arm and lets them drop, attempting to have them land on his foot directly below his hand.

Standing stationary on the station platform, Susie watches the train leave, and notices Fred dropping his keys. Which of the following statements about the trajectory of the keys is correct?

A) Both Fred and Susie observe it to be curvilinear.

B)

Both Fred and Susie observe it to be rectilinear.

C)

Fred observes it to be curvilinear and Susie observes it to be rectilinear.

D)

Fred observes it to be rectilinear and Susie observes it to be curvilinear.

A hot air balloon is travelling vertically. When the balloon is 100 m above the ground, a sandbag is dropped

and hits the ground 4.7 seconds later.

What was the velocity of the balloon at the instant the sandbag was released?

A) 1.8 m/s [downward]

B) 1.8 m/s [upward]

C) 44 m/s [downward]

D) 44 m/s [upward]

A police officer was sitting in his stationary patrol car waiting to catch a speeding vehicle. A car passed the

officer at a constant speed of 72 km/h. The instant it passed, the officer accelerated uniformly to 90 km/hour

in 10 seconds and continued at that speed until he caught up with the speeding vehicle.

How far had both vehicles travelled when the officer caught up with the speeding car?

While standing at the top of the Grand Canyon, Heather throws a rock with an upward velocity of 35.0 m/s.

The rock hits the bottom of the canyon 22.5 s later.

How deep is the canyon at this point?

A) 677 m

C)

2480 m

B)

1690 m

D)

3270 m

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On her trip to school, Danielle makes several stops as illustrated in the scaled diagram below.

Home School

Store

Coffee

shop

Friend’s

house

Which vector represents her resultant displacement?

A)

C)

B)

D)

Aeron and Cynthia are runners on the school relay team. On the exchange of the baton between them, Aeron

enters the exchange zone with a speed of 9.00 m/s. At the same instant, Cynthia is 5.00 metres ahead running

with a speed of 7.00 m/s. Each girl runs at a constant speed.

An aerial view of the exchange zone at this instant is shown below.

5.00 m

v C = 7.00 m/s

v A = 9.00 m/s

How far will Aeron run before she catches up with Cynthia?

Show all your work.

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Which of the following graphs represent non-uniform motion?

t

d v v

3 4 1 2

a

t t t

A)

1 and 2

C)

2 and 3

B)

1 and 4

D)

3 and 4

Mike forgot to leave his wife’s keys in their apartment, so he decided to throw them up to her. She was

standing on a balcony 4.0 m above him. He threw the keys straight up with a velocity of 12.0 m/s. His wife

missed the keys on the way up, but caught them as they were coming down.

For how many seconds were the keys in the air?

Show all your work.

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What additional force (magnitude and direction) is needed to put the following forces in equilibrium?

(Diagram is not drawn to scale)

F3 = 20 N [N60°W]

F1 = 30 N [E]

F2 = 45 N [S]

Show all your work.

Pat and Ryan are arguing about who can throw a football higher. Pat decides to throw the ball first and he

sends it straight up at a velocity of 32 m/s. Unfortunately, he does not notice a bird flying 25 m above him, and

he hits the bird. (Assume air resistance is negligible.)

At what velocity is the ball travelling at the instant it hits the bird?

A) 15 m/s

C)

39 m/s

B)

23 m/s

D)

534 m/s

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The graph below displays the velocity of a body in motion over time.

50 100 150 200 250 300 350 400

2000 150 0 1000 500

Velocity (m/s)

Time (s)

How many metres has the body travelled in 5 minutes?

A)

250 000 m

C)

350 000 m

B)

300 000 m

D)

450 000 m

To get from his house to the houses of four of his friends, Serge must travel in different directions, as indicated

below.

Archie: 4.8 km N; 3.2 km W

Barry: 20 km N; 15 km S

Chris: 3 km N; 7 km S45°E

Steve: 3.5 km S; 1 km E; 2 km S

A visit to which friend would result in the greatest total displacement from Serge’s house?

A) Archie

C)

Chris

B)

Barry

D)

Steve

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Moria dropped a heavy object from a height of

9.0 m above a pile of cardboard. After the object

came to a stop, Moria determined that the

cardboard was deformed to a depth of 0.40 m.

Before

9.0 m

0.40 m

After

What resulting deceleration did the object undergo while in contact with the cardboard?

A) 1.3 100 m/s2

C)

1.3 101 m/s2

B)

9.8 100 m/s2

D)

2.2 102 m/s2

Ali is participating in the Tour de l’Île bicycle marathon held each year on the island of Montreal. The following

velocity versus time graph represents Ali’s course over a period of 1800 seconds.

Velocity-time Graph of Ali’s Bicycle Race

Velocity (m/s)

Time (s)

10.0

-10.0 200 600 1800

1160

From the graph determine the following:

1. Ali’s acceleration at 400 seconds.

2. Ali’s acceleration at 1200 seconds.

3. Ali’s displacement during the period between 800 seconds and 1400 seconds into the ride.

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During a power play attack in a hockey game, player A passes the puck to player C, who passes the puck to

player B, who shoots the puck at the net and the goalie (D) catches it.

A

C

B

D

Which vector best represents the displacement of the puck?

A)

C)

B)

D)

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A cart, starting from rest, rolls down a ramp.

A "ticker tape" attached to the rear of the cart passes through a

timing device that marks the tape every tenth of a second.

Timing device

Ticker tape

Which ticker tape below shows the motion of the cart?

A) Ticker Tape 1

Start Finish

B) Ticker Tape 2

Start Finish

C) Ticker Tape 3

Start Finish

D) Ticker Tape 4

Start Finish

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Examine the position-time graph below.

d (m)

t (h)

Which of the following most accurately describes the motion represented in the graph?

A) Increasing velocity, followed by constant velocity, followed by increasing velocity

B)

Increasing velocity, followed by zero velocity, followed by increasing velocity

C)

Constant velocity, followed by constant velocity, followed by constant velocity

D)

Constant velocity, followed by zero velocity, followed by constant velocity

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The graph below represents the velocity of a dandelion seed blowing in the wind for 20 seconds.

Velocity (m/s)

10

20

30

40

- 10

- 20

- 30

- 40

Time (s)

2 4 6 8 10 12 14 16 18 20

Velocity vs Time Graph

0

What is the displacement of the dandelion seed from the 4th second to the 20th second?

A) 145 m

B)

185 m

C)

325 m

D)

365 m

Laura propels a stone straight up with her slingshot. The stone strikes a tree branch 4.0 m above her. It strikes

the branch with a velocity of 5.0 m/s.

How long does this take?

A) 0.42 s

B)

0.53 s

C)

1.6 s

D)

10 s

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During a Quidditch match, Potter and Malfoy are chasing the snitch. Trying to catch the snitch first, Malfoy

dives off his broom at 2 m/s [Down], from a height of 20 m from the snitch, while Potter is racing towards the

snitch at a constant speed of 25 m/s for 75 m.

Who will make it to the snitch first and with how much time to spare? (Assume the snitch is at rest.)

Titov and Dimitri are travellers on the Siberian Railway. Titov’s train leaves Irkutsk for Krasnoyarsk travelling at

an average speed of 42.0 m/s. Dimitri’s train leaves Krasnoyarsk 30 minutes later heading towards Irkutsk on a

parallel track and travelling at an average speed of 28.0 m/s. Titov’s train travels for 5.00 hours before meeting

Dimitri’s train.

What is the distance in kilometers between the two cities?

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The following path was traced by an object during an experiment in a laboratory.

When observed from a stationary vantage point, which of the following would NOT cause the trajectory

above?

A) A goal kick from the soccer goal keeper, into the air, towards the half way line

B) A package dropped from a plane flying horizontally

C) An arrow shot upwards at an angle of 45 degrees

D) A kangaroo hopping along a path

The International Space Station (ISS) orbits in space at a velocity of 7.6 km/s. During one of their missions, the

astronauts onboard the station launched a satellite with a velocity vector, as shown below. Seconds after the

launch, the satellite stopped working. A rocket was immediately launched from Earth to retrieve the satellite.

11.3 km/s

Space Station 7.6 km/s

Satellite

Given the following:

The escape velocity of the rocket to leave

Earth’s gravitational pull is 11.3 km/s

vertically.

The space station was directly over the

rocket-launching platform at the time the

space station was launched.

The magnitude of the satellite’s velocity

vector is less than that of the space station.

Which of the following velocity vectors represents the direction that the rocket takes to reach the disabled

satellite?

A)

C)

B)

D)

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A student dropped an object vertically and measured the time it took for the object to fall a certain distance.

She collected her data and proceeded to analyze it. One of the graphs she plotted was acceleration vs. time.

Which graph corresponds to her experiment?

A)

Time

Acceleration

C)

Time

Acceleration

B)

Time

Acceleration

D)

Time

Acceleration

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