Kinesiology Exam 5
Which of the following is Newton's Law of Inertia?
A body in motion tends to remain in motion at the same speed in a straight line unless acted on by a force.
Which of the following terms is defined as the rate of change in velocity?
Acceleration
Which of the following statements is true about kinetic friction?
It is the friction between two objects that are sliding along each other.
Which of the following is the most common form of simple machine found in the human body?
Levers
Which of the following types of machine is most common in the musculoskeletal system arrangements of the human body?
Levers
For two objects in contact with each other which of the following would result in the greatest amount of friction?
One object sitting stationary on the other
Which of the following is not among the general factors that positively affect the achievement of balance?
The center of gravity falls outside the base of support
A .145 kg baseball is traveling at 40m/s. How much work must be done to catch it.
-116 J
Which is true when applying Newton's 3rd law of action/reaction to dribbling a basketball?
action: ball hits floor; reaction: floor pushes ball
What type of motion is exhibited by the leg segments of a sprinter running a 100 meter dash?
angular
Which of the following actions increase torque?
apply greater force AND apply force at an angle closer to 90 degrees AND lengthen perpendicular distance between axis and point of application of force
The point at which all of the body's mass and weight is equally balanced or equally distributed in all directions is the _____.
center of gravity
What does the center of gravity of an object represent?
center of mass of body
What is meant by torque?
effective force producing rotary motion at an axis
Why is a second-class lever well adapted to moving heavy loads?
effort arm is longer than resistance arm
Kinematics is concerned with the description of motion and includes consideration of each of the following except:
force
Kinematics is the description of motion and includes consideration of each of the following except?
forces
Which of the following defines the center of gravity of the body?
intersection of cardinal sagittal, horizontal and frontal planes
Mass is
inversely proportional to acceleration the quantity of matter contained in an object a measure of inertia
In which of the following is torque not found?
linear motion
What is the relationship between the angular and linear velocities of a lever?
linear velocity is equal to the angular velocity times the length of the lever
What is the primary factor affecting the stability of an object?
location of center of gravity
What is weight?
mass times acceleration due to gravity
Why is it easier for a runner to move his recovery leg forward more rapidly when it is flexed than when extended?
moment of inertia of the leg is less when leg is flexed
Which is an example of linear motion in sport?
movement of the center of gravity of a putted golf ball
Which of the following statements is false regarding forces?
none, they are all true: Product of mass and acceleration, May either push or pull on an object, Without forces acting on an object there would be no motion
How much work is done if you hold a tennis racquet in your hand without moving it?
none: a large amount, a small amount, depends on size of racquet
What is the true effort arm (moment arm) of a lever in the body?
perpendicular distance from line of pull of muscle to axis
What determines the type of motion of a freely moveable object?
point at which force is applied
Which type of motion is produced by any force that is not through the axis of rotation?
rotary
Why lift a heavy weight by flexing and then extending the knees rather than flexing at the hips and then lifting the trunk?
shorter resistance arm
An individual is expecting to be pushed from the left side. What would be the best standing position to assume in order to absorb the force without losing one's balance?
side stride stance, line of gravity towards left edge of base of support
Why is it more difficult to perform a sit-up when the hands are clasped behind the head than when the arms are kept at the side?
the resistance arm is greater
Which of the following must be true in order for a state of equilibrium to exist?
the sum of all forces and torques acting on the object must equal zero
Change in momentum is the result of an impulse. How may the impulse be changed?
time of application of force
Which of the following motions should be avoided in working with long handled implements?
twisting
To take a step, one must become ____ and then ____ to walk from from one place to another.
unstable, stable
Power equals
work ÷ time
What is the acceleration when the velocity of an object is constant?
zero
Which of the following represents a scalar quantity?
a mass of 70 kilograms