Biomechanics Exam 5 review

150 Nm

A perpendicular force of 300 N is applied to a door 0.5 m from the hinges. What is the torque? 0.5 Nm 150 Nm 300 N/m 600 N/m none listed

EA = 10", RA = 5"

Based on the principles of levers, which of the following levers is most efficient in overcoming a resistance of 20 lbs? EA = 2", RA = 4" EA = 4", RA = 6" EA = 10", RA = 5" EA = 10", RA = 10"

One object sitting stationary on the other

For two objects in contact with each other which of the following would result in the greatest amount of friction? One object sliding across the other One object sitting stationary on the other One object rolling across the other The amount of friction would be the same in all of the above examples

all of the listed answers are correct

Force is defined as any influence tending to _____ motion. all of the listed answers are correct two of the listed answer are correct modify change cause

784.8 Newtons, 176 pounds

If a person has a mass of 80 kg, what is their weight? (multiple answer) 80 Newtons 80 pounds 784.8 Newtons 176 pounds 176 Newtons none of the listed answers

10987 J

If a person runs up a flight of 70 steps in 28 seconds. If each step is 20 cm and the person weights 176 lbs. How much mechanical work was done? 784.5 J 1120 J 1400 J 10987 J none listed

linear motion

In which of the following is torque not found? linear motion bowling ball rolling down alley seesaws animals

force

Kinematics is concerned with the description of motion and includes consideration of each of the following except: displacement. force. velocity. time

Forces

Kinematics is the description of motion and includes consideration of each of the following except? Time Displacement Velocity Forces

center of gravity

The point at which all of the body's mass and weight is equally balanced or equally distributed in all directions is the _____. balance point point of equilibrium axis center of gravity

168 J

The potential energy of a .045 kg golf ball before it is dropped off the empire state building (381 meters) is approximately 168 J 17 J none of the listed answers is correct 3734 J

mass

The weight of a body is defined as a quantification of the force of gravity acting on which aspect of the body? weight mass resistance inertia

point at which force is applied

What determines the type of motion of a freely moveable object? location of center of gravity shape of object point at which force is applied amount of force applied

speed

What does a machine with a resistance arm greater than a force arm favor? torque acceleration speed force

center of mass of body

What does the center of gravity of an object represent? geometric center exact center anatomically center of the base of support center of mass of body

resistance to change in motion

What is inertia? resistance to change in motion tendency of an object to rotate effect of one object on another rate of change in motion

perpendicular distance from line of pull of muscle to axis

What is the true effort arm (moment arm) of a lever in the body? perpendicular distance from line of pull of muscle to axis distance from midpoint of muscle's line of pull to axis distance from axis to point of attachment of muscle perpendicular distance from axis to point of application of force

mass times acceleration due to gravity

What is weight? friction times base of support mass times acceleration due to gravity gravitation times density size times base of support

angular

What type of motion is exhibited by the leg segments of a sprinter running a 100 meter dash? linear angular constant translatory

vertical velocity equals 0, kinetic energy equal 0

When you throw a ball into the air and it reaches its peak in flight, which of the following is true? (do not consider air resistance) horizontal velocity equals 0 kinetic energy equal 0 potential energy equal 0 vertical velocity equals 0

movement of the center of gravity of a putted golf ball

Which is an example of linear motion in sport? movement of the center of gravity of a putted golf ball arm movements of a shot putter movement of center of gravity of a diver leg movements of a sprinter

action: ball hits floor; reaction: floor pushes ball

Which is true when applying Newton's 3rd law of action/reaction to dribbling a basketball? action: ball hits floor; reaction: floor pushes ball action: ball hits floor; reaction: ball force on hand action: floor pushes ball; reaction: ball hits floor action: ball leaves hand; reaction: ball hits floor

All of the above

Which of the following could be done to reduce the amount of force needed to move a lever? Move the resistance closer to the axis Apply the force further from the axis Decrease the amount of resistance two of the listed answers All of the above

intersection of cardinal sagittal, horizontal and frontal planes

Which of the following defines the center of gravity of the body? intersection of cardinal sagittal, horizontal and frontal planes intersection of cardinal sagittal and horizontal planes two of the listed answers are correct intersection of cardinal sagittal and frontal planes intersection of cardinal frontal and horizontal planes all of listed answers is correct

intersection of cardinal sagittal & frontal planes AND vertical line passing through center of gravity

Which of the following defines the line of gravity of the body? intersection of cardinal sagittal & frontal planes AND vertical line passing through center of gravity intersection of cardinal sagittal & horizontal planes AND vertical line bisecting the body laterally vertical line bisecting the body laterally intersection of cardinal sagittal & frontal planes

Enhances force in an attempt to increase total force needed to overcome a resistance

Which of the following does not describe a way in which machines function? Balance of multiple forces Enhances force in an attempt to increase total force needed to overcome a resistance Enhance range of motion & speed of movement so that resistance may be moved further or faster than applied force Alter resulting direction of the applied force

A change in the acceleration of a body occurs in the same direction as the force that caused it.

Which of the following is the Law of Acceleration? For every action there is an opposite and equal reaction. A body in motion tends to remain in motion at the same speed in a straight line unless acted on by a force. A change in the acceleration of a body occurs in the same direction as the force that caused it. None of the above choices is correct. two of the listed answers are correct

2nd class with resistance arm of 10 and force arm of 20

Which of the following levers would be best to use to move a specific object if your only objective was slight movement of the object? 1st class with resistance arm of 10 and force arm of 10 2nd class with resistance arm of 10 and force arm of 20 3rd class with resistance arm of 20 and force arm of 10 Each would be just as effective as the others

A third-class lever with a resistance arm of 20 and a force arm of 10

Which of the following levers would be best to use to move a specific object if your only objective was speed of the object's movement? A third-class lever with a resistance arm of 20 and a force arm of 10 Each lever would be just as effective as the others A second-class lever with a resistance arm of 10 and a force arm of 20 A first-class lever with a resistance arm of 10 and a force arm of 10

twisting

Which of the following motions should be avoided in working with long handled implements? pulling twisting pushing lifting

the sum of all forces and torques acting on the object must equal zero

Which of the following must be true in order for a state of equilibrium to exist? all linear forces acting on the object must be balanced, torques may be unbalanced neither torques nor linear forces acting on the object must equal zero the sum of all forces and torques acting on the object must equal zero all torques acting on the object must be balanced, linear forces may be unbalanced

a mass of 70 kilograms

Which of the following represents a scalar quantity? a mass of 70 kilograms a velocity of 30 m/s a displacement of 5 feet a muscle force of 10 Newtons

Angular motion of the joints produces linear motion.

Which of the following statements accurately describes the relationship between linear and angular motion? Angular motion of the joints produces linear motion. linear Motion of the joints produces angular motion. Both of the above choices are correct. None of the above choices is correct.

a 14 lb. bowling ball with a linear velocity of 35 ft/sec will have greater momentum than a 8 lb. ball at 50 ft/sec

Which of the following statements is correct concerning momentum? at the same velocity, a badminton racquet will have greater momentum than a tennis racquet a softball bat weighing one-third that of a second bat but swung at twice the velocity will have greater momentum given equal linear velocity just after impact, a tennis ball will have greater momentum than a tennis racquet a 14 lb. bowling ball with a linear velocity of 35 ft/sec will have greater momentum than a 8 lb. ball at 50 ft/sec

The closer the force application is to the axis of rotation the greater the amount of resistance that can be moved

Which of the following statements is false regarding the proportional relationship between force components and resistance components? The closer the force application is to the axis of rotation the greater the amount of resistance that can be moved If either of the resistance components increase, there must be an increase in one or both of force components The greater resistance or resistance arm requires greater force or longer force arm The greater the force or force arm allows a greater amount of resistance to be moved or a longer resistance arm to be used none listed, they are all true

Levers

Which of the following types of machine is most common in the musculoskeletal system arrangements of the human body? Pulleys Wheel-axles Levers None of the above choices is correct

rotary

Which type of motion is produced by any force that is not through the axis of rotation? linear rotary straight line motion rectilinear

face box with elbows bent and arms close to body

Which would be the most efficient manner in which to lift a heavy box? grasp box at arms length turn side to box and lift with one arm place one hand under box and one hand on top at arms length face box with elbows bent and arms close to body

moment of inertia of the leg is less when leg is flexed

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 mass of the leg is less when it is flexed mass of the leg is greater when it is flexed moment of inertia of the leg is greater when leg is flexed

the resistance arm is greater

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 torque of the resistance is reduced the torque produced by the abdominals is reduced the resistance arm is greater the resistance arm is smaller