High School
SAT
SAT Elite 1500
SAT Tutoring
ACT
ACT Elite 33
ACT Tutoring
University
MCAT
MCAT Elite 515
Med-School Admissions
Pre-Med Tutoring
Pre-Med Plus
LSAT
LSAT Elite 170
LSAT Self-Paced
LSAT Tutoring
DAT
DAT Elite
DAT Tutoring
Log in
Get Started for Free
Franklin is coming over to your house. He first travels at 3m/s East, and then …
Related Topics
Wize University Physics Textbook (Master) > Motion in 1/2/3D: Kinematics
Relative Velocity
3 Activities
Wize University Physics Textbook (Master) > Motion in 1/2/3D: Kinematics
Basic Concepts of Kinematics
5 Activities
Franklin is coming over to your house. He first travels at 3m/s East, and then he travels 3m/s South. What direction is his average acceleration?
South
East
Southeast
Northwest
Southwest
No acceleration
I don't know
Check Submission
More Relative Velocity Questions:
Relative velocity
Dave swims at a constant 2.5 m/s across a river flowing at 2 m/s. What is the:
(a) the relative velocity of Dave, and
(b) what is Dave's direction of travel, with respect to the ground?
In an elevator going up at constant speed, you drop your wallet.
a) Will it hit the ground faster, slower, or in the same amount of time compared to a situation where the elevator was at rest? Explain your answer.
b) What if the elevator was initially at rest and started moving while your wallet was falling to the ground? Explain your answer.
Andy is trying to catch a bus, but the bus is pulling away already at 40.0
o
from +x axis at 5.0m/s. Bob sitting in the bus sees Andy running at 48.6
o
below the -x axis with a speed of 4.28m/s.
How fast was Andy running and in what direction?
Relative velocities example
Say you are on the ground, outside, controlling a drone video camera. In your video, it seems like a bird flew by at 5.0 m/s southwest. From your point of view on the ground, the bird flew 1.0 m/s northwest. What is the velocity of your drone relative to you on the ground? Give your answer in terms of magnitude and the angle relative to the +x axis.
Turning acceleration
Joe is running 10m/s to the east. And then he's running 10m/s to the south. What direction is his average acceleration?
Practice Example: Relative Velocity
A pilot in a Boeing 747 is beginning a 1500km flight. The plane's speed is 1000km/h and air traffic control says that he will have to head
15
o
15^o
1
5
o
west of south to maintain a southward course. If the flight takes 100min, what is the wind speed?
Relative velocity
A duck swims at a constant speed from one side of a river to the other side in a time of 4 seconds. The river is 6 meters wide and it is flowing at a speed of 2 m/s. What is the
(a) the velocity of the duck and
(b) what is its direction of travel, with respect to the ground?
Practice: Relative Velocity 2
A train travels at 50 m/s to north with respect to the ground. A boy on the train runs at 10m/s to the south with respect to the train. Find the velocity of the boy with respect to the ground.
I want to direct a remote-control toy boat due west across a river, but my jerk friend Dave broke the rudder, so I can’t turn mid-journey. The boat travels at a speed of 8 m/s, and the river is flowing south at 5 m/s. What direction should I point my boat?
A pilot in a Boeing 747 begins a 1500-km flight. The plane's speed is 1000 km/h, and air traffic control says you'll have to head 15
o
west of south to maintain a southward course. If the flight takes 100 min, what's the wind velocity?
A pilot in a Boeing 747 is beginning a 1500 km flight. The plane's speed is 1000 km/h and air traffic control says that he will have to head 15
o
west of south to maintain a southward course. If the flight takes 100 minutes, what is the wind velocity? (Enter your answer to three sig figs, in units of km/h.)
More Basic Concepts of Kinematics Questions:
If you walked 3.00km West, and then 5.00km South to get to the store, what angle are you traveling at relative to the South direction? What is the magnitude of your displacement?
If you walked 3.00km West, and then 5.00km South to get to the store, what angle are you traveling at relative to the South direction? What is the magnitude of your displacement?
Practice question: position, velocity, and acceleration
The position of a particle is given by
r
⃗
(
t
)
=
(
10
t
+
t
2
+
7
)
m
\vec{r}(t)=(10t+t^2+7)m
r
(
t
)
=
(
10
t
+
t
2
+
7
)
m
a) Calculate instantaneous velocity at t =5 sec
Practice question: position, velocity, and acceleration
The position of a particle is given by
r
⃗
(
t
)
=
10
t
+
t
2
+
7
\vec{r}(t)=10t+t^2+7
r
(
t
)
=
10
t
+
t
2
+
7
Calculate instantaneous velocity at t =5 sec, average velocity for interval (3-5 sec). Also calculate instantaneous acceleration at t =1 sec.
Forces: Friction
A professional mover drags a 20kg mattress across the floor. The mover exerts a force of 50 N at 30° to the horizontal. The coefficient of kinetic friction is 0.100. What is the acceleration of the mattress?
I'm moving and packed all my books into a box that weighs 17kg. I pull the box on a weightless dolly with a force of 60N at an angle of 30° to the horizontal surface.
a) What is the acceleration of the box?
b) The box feels the normal force from the ground and the force of gravity. Are the normal force and gravity an action-reaction pair? Explain your answer!
Practice: Distance and Displacement
You drive 200 kilometres west to get from Montreal to Ottawa. On the way back to Montreal, you run out of gas after driving 50 kilometres.
Two runners (Bob and Alice) are racing. Alice is much faster than Bob and is placed such that she starts
25
m
25\ m
25
m
behind Bob. She is
1.5
1.5
1.5
times faster than Bob who runs at
8
m
/
s
8\ m/s
8
m
/
s
.
a) If they both start at the same time, when are these runners at the same point on the track?
b) Who will win in a
1000
m
1000\ m
1000
m
race if Alice has to start
200
m
200\ m
200
m
behind? Explain your answer.
Throwing a rock down a well
Joe throws a rock straight down a well. He throws it at 13.0m/s, and the well is 5.10m deep. What is the velocity of the rock when it gets to the bottom? Use the conventional coordinates, where up is positive.
In horse racing, units of "horses" are used to measure length. It is defined as the length of a horse, or 8ft. And there are 3.28ft in 1m.
In the 1973 Belmont race, the horse Secretariat (great movie) won by 31 horse lengths. What is that distance in cm?
Riding a ferris wheel
Joanne is riding a ferris wheel that is 100.0m in diametre. Starting at the bottom, she rides 2 and 3/4 revolutions before the wheel gets stuck.
If you walked 3.00km West, and then 5.00km South to get to the store, what angle are you traveling at relative to the South direction? What is the magnitude of your displacement?
A rabbit, escaping a fox, runs 40
o
north of west at 10.0m/s. A coordinate system is established with the positive x-axis to the east and the positive y-axis to the north. Write the rabbit’s velocity in terms of components and unit vectors.
Taron is off on a rocket. He starts off at Earth, and launches off at 9am. He flies up 200km by 10am, and then another 150km by noon. He returns to Earth at 1:30pm. Give all answers in SI units.
(NB: the video says the trip ends at 2:30pm, this is incorrect. Should be 1:30pm, and the mathematics is still fine.)
a) What was his average speed for the whole trip?
Vanessa is making her way downtown, moving quite fast. She's racing Adam who's in a big yellow taxi. Their velocities are shown below
Over the entire race, who travelled the longest distance? Who has the greater displacement?
Average acceleration of runner
Frank is running at 3.0m/s. He accelerates until he is travelling at -1.3m/s. What is his average acceleration if it took him 12.0s to do this?
A bird flew 100m to the east then 200m to the northwest. Use the algebraic addition of vectors to find the bird’s net displacement.
A 20.0kg cart is moving at 10.0m/s before it goes down a hill. It ends up 2.0m below where it started, and travelled a distance of 15.0m. What is the speed of the car? There is friction, and it applies an average force of 2.00N over the course of it's motion.
Give your answer in m/s.
I over-packed a box and it weighs 50kg. I'm pulling it across a rough surface at an angle of 45 degrees above the horizontal with a force of 280N. The coefficient of kinetic friction of the floor is 0.5. I pull for 10 seconds, the box speeds up from rest, I release it and it continues to slide to a halt. What is its maximum speed?
Area under plot for displacement
Alice and Bob are having a race. Alice starts off strong, at 10.0m/s, while Bob struggles at 5.0m/s. But 5 minutes later, Alice starts to tire out, and slows to 2.0m/s. Bob sees his chance, and starts running at 7.0m/s. The race ends another 5 minutes later. Who travelled the furthest, winning the race?
Direction of acceleration
Joe is running from 20m to 10m, while he is slowing down. What direction is his acceleration?
If you walk around a circle of diameter of 10 m for π rad, how far have you walked?
Enter answer in meters.
Kinematics question
The slope of position-time graph gives
average velocity
Practice question: position, velocity, and acceleration
The position of a particle is given by
r
⃗
(
t
)
=
10
t
+
t
2
+
7
\vec{r}(t)=10t+t^2+7
r
(
t
)
=
10
t
+
t
2
+
7
Calculate instantaneous velocity at t =5 sec, average velocity for interval (3-5 sec). Also calculate instantaneous acceleration at t =1 sec.
A 200g mass block is released from rest at a height of 25 cm on 30
o
incline. The incline is frictionless. It slides down the incline and then a frictionless surface until it collides elastically with an 800g block at rest 1.4 m from the bottom of the incline as shown in the figure. How much later do the two blocks collide again?
If the velocity of particle is non-zero. Can acceleration of particle be zero?
If the average velocity of an object is zero in some time interval, object's displacement is
zero
The position of a particle of mass 2g is given by
r
⃗
=
−
3
t
2
i
^
+
2
t
j
^
+
5
k
^
\vec{r} = -3t^2\hat{i}+2t\hat{j}+5\hat{k}
r
=
−
3
t
2
i
^
+
2
t
j
^
+
5
k
^
(t is in sec and r is in m).
The magnitude of instantaneous velocity and the magnitude of instantaneous acceleration at t = 3s are:
Practice question: position, velocity, and acceleration
The position of a particle is given by
r
⃗
(
t
)
=
(
10
t
+
t
2
+
7
)
m
\vec{r}(t)=(10t+t^2+7)m
r
(
t
)
=
(
10
t
+
t
2
+
7
)
m
a) Calculate instantaneous velocity at t =5 sec
b) Calculate the average velocity for an interval (3-5 sec).