Transcript LOCOMOtion - TeacherWeb

LOCOMOTION
Study Guide Review
1. Drag force would affect which of
the following?




A.
B.
C.
D.
A runner’s shoes on the sidewalk.
A fish’s fins in the water.
A bird’s wings in the air.
B and C.
A cat is chasing a mouse in a straight line. Suddenly
the mouse turns and runs in a different direction. Use
the concept of Newton’s Third Law to describe how the
cat can change direction to follow the mouse.
A: In order to change direction, the cat must apply a
force to the ground. According to Newton’s Third Law,
when the cat exerts a force on the ground, the ground
will push back with an equal and opposite force. By
exerting force on the ground away from the mouse,
the ground will push the cat in the direction of the
mouse.
2.
True or False: Stride length is determined by the number
of legs that an animal has.
A: False
4.
Kyle is two meters tall. Liz is one meter tall. When they
hike together, Liz often complains that they are walking too
fast, but Kyle disagrees; he never feels like they are
walking quickly. What might be the cause of their
disagreement?
A: As leg length increases, stride length increases. Since Kyle
is taller than Liz, he probably has longer legs and a larger
stride length than Liz. If this were the case, his legs would
cover more distance than Liz. Liz would therefore have to
move her legs faster to keep up.
3.
True or False: Decreasing the total surface area on a bird’s
wings increases the drag force it experiences when falling to the
ground.
A: False
5.
6.
A tiger’s paws and a dolphin’s fins are very different in shape.
Explain how both creatures use force to move through their
environment.
A: Because both animals have different limbs and environments, they
must generate different types of force to locomote. The tiger,
moving on land, must exert force on the ground with its paws.
The Earth will push back and move it forward. The dolphin
instead must exert force on the water with its fins. This will cause
the water to push back, moving the dolphin forward.
7.
A.
B.
C.
D.
When a frog swims through water, it often needs
to adjust the drag force it encounters. How can
the frog reduce drag force as it swims?
Closing its webbed feet.
Spreading its webbed feet out.
Increasing the speed of its leg movement.
A and C.
True or False: If the Earth’s surface didn’t exert force,
then no movement on the ground would be possible.
A: True
9.
We can determine the velocity of which of the
following?
A.
A car driving 100 km/h.
B.
A bike moving north at 20 m/s.
C.
A fish swimming at 0.1 m/s.
D.
A and C.
8.
10.
A.
B.
C.
D.
A dog is running in a straight line down a
sidewalk. She wants to stop. In which direction
does the dog need to exert force in order to slow
down?
In the direction she’s running.
In the opposite direction that she is running.
To the left side of her body.
None of the above.
11.
A.
B.
C.
D.
A fish is swimming through the ocean at 10 cm/s. It
suddenly speeds up to 30 cm/s to avoid a
predator. After avoiding the predator, it slows
down to 5 cm/s. At what point does the fish
experience the most drag force?
Swimming 10 cm/s.
Swimming 30 cm/s.
Swimming 5 cm/s.
It experienced equal drag force at every speed.
12.
A.
B.
C.
D.
When we walk, our feet apply force to the
ground. How much force does the ground push
back with?
The ground pushes back with more force.
The ground pushes back with equal force.
The ground pushes back with less force.
The ground does not push back with any force.
Michael’s bike exerted force on the Earth, and is
bike moved forward. Why did this happen?
A: The Earth has more mass than the bike.
14. State Newton’s First Law of Motion.
A: An object in a state of uniform motion stays in that
state unless acted upon by an outside force.
15. State Newton’s Third Law of Motion.
A: For every force there is an equal and opposite
force.
13.
What is an adaptation?
A: Adjustment to environmental conditions;
modification of structure of a population of
organisms that makes the organisms more fit for
existence under the conditions of their environment.
17. What is surface area? How do you calculate it?
A: The amount of the surface that covers the object in
question or that an object covers. It is calculated
by multiplying height by width.
16.
A push or pull on an object is a __________.
A: Force
19.
How does Newton’s Third Law of Motion apply to the movement of
animals on land?
A: In order for a human or animal to walk on land, a force is needed.
As a step is taken, a force is exerted on the Earth. The Earth
exerts an equal force in return and in the opposite direction of the
original force. When the direction of an animal or a person
changes or when they slow down or speed up, forces are exerted
to which the Earth exerts an equal and opposite force in return.
This application of equal an opposite forces, as described in
Newton’s third law of motion, gives humans and animals the ability
to locomote and, therefore, survive in their environment.
18.
How do physical characteristics of a land animal
determine its ability to move?
A: As leg length increases, stride length also
increases. Therefore, on would assume that stride
rate, or the number of strides in a given period of
time, is also related to leg length. This relationship
may allow greater equivalence between prey and
predator. Organisms with shorter limbs must take
more strides per unit of time than an organism with
longer limbs.
20.
What is drag force? How did we demonstrate it in
lab?
A: Drag force is the resistance applied to an object
by a fluid. Drag force always acts opposite to the
direction of relative motion. We demonstrated this
in lab when we used the spring scales to pull the
ruler across the water.
21.
How are forces and motion of organisms in water
similar or different to organisms that locomote on
land?
A: Organisms on both land and water must adapt to
forces present. On land, organisms exert a force on
the ground in order to locomote, and the ground
exerts an equal force in the opposite direction in
response. In water, organisms such as fish and ducks,
exert a force on the water in order to locomote and
the water exerts an equal force in the opposite
direction. When a duck pushes with its webbed feet,
the opposite and equal force encountered by the
force exerted by the duck is called drag force.
22.
Think of the way a fish is shaped, with a small front surface
area and a large side surface area. How does the fish’s
shape relate to the relationship between the surface area
and drag force?
A: The front of a fish has a small surface area, which
minimizes the amount of drag force that acts upon it as it
moves forward. The fish’s largest surface area is on its
sides. This maximizes the amount of drag force that acts
upon it as it swims. The fish moves forward because there
is a greater amount of drag force acting on the sides than
on the front of the fish, and because the force exerted by
the fish as it pushes against the water is less than the drag
force exerted on its sides. Therefore, the fish’s shape
allows it to move easily through the water.
23.
How does the adaptation of a duck’s webbed feet affect
its movement in the water? Explain your answer in terms of
the relationship between drag force and surface area.
A: A duck pushes against the water with its open webbed feet,
propelling itself forward, then curls its toes and pulls its
feet against its body as it move the feet forward for
another stroke. The duck is using drag force to its
advantage by pushing against the water with its open
webbed feet. Drag force is the force that pushes the duck
forward in the water. Therefore, the duck uses the large
surface area of its open webbed feet to increase drag
force. The duck minimizes drag force when it pulls its
folded feet forward beneath its body.
24.
How does the effect of drag force on surface area
affect flying animals?
A: As surface area increases, drag force increases. Drag
force acts in the opposite direction of an object’s fall,
thus slowing the object’s descent. Wings increase the
surface area of birds. The increases surface area
decreases a bird’s chances of falling to the ground. If
birds did not have wings, and instead had limbs like
animals that live on the ground, their surface area
would be greatly reduced, thereby decreasing their
drag force when descending.
25.