Biomechanics Exam 2

The energy a system possesses because of the motion of the system is also known as what?

-Elastic energy

-Kinetic energy

-Strain energy

-Potential energy

Kinetic Energy 

Which of the following mechanical quantities best describes explosive track and field events, such as the long jump and the shot put?

 

-mechanical power

-potential energy

-kinetic energy

-mechanical energy

Mechanical Power

Negative mechanical work involves which of the following? 

-the direction of the net force is in the opposite direction as the motion

-none of the options are correct

-the direction of the net force is in the same direction as the motion

-concentric muscle contractions

The direction of the net force is in the opposite direction as the motion

The components of mechanical work include which of the following? 

 

-power and displacement

-force and displacement that are parallel to each other

-acceleration and time

-force and displacement regardless of the direction of one relative to the other

-force and time

Force and displacement that are parallel to each other

What type of energy is strain energy? 

 

-potential

-caloric

-kinetic 

-entropic

Potential

The capacity for doing work that a body possesses because of its height or position is called what? 

 

-potential energy

-kinetic energy

-moment of inertia

-mechanical power

Potential Energy

Which of the following mechanical quantities are not dependent on time? Choose all that apply.

 

-Velocity

-Power

-Kinetic energy

-Potential energy

Mass?

New ice hockey blade designs have resulted in extremely low values for the kinetic friction coefficients of ice hockey skates on ice than older designs, allowing for players to skate faster with less effort. 

-True

-False

True 

Which of the following is/are true statement(s) regarding the law of gravitation?  Select all options that are correct.

-It determines the acceleration due to gravity

-All bodies are attracted to one another with a force proportional to the product of their masses

-All bodies are attracted to one another with a force inversely proportional to the square of the distance between them

-All bodies are attracted to one another with a force proportional to the product of their masses

-All bodies are attracted to one another with a force inversely proportional to the square of the distance between them

-It determines the acceleration due to gravity

Which of the following statements are true for an object of constant mass that is in motion with a constant momentum? Select all options that are correct.

-acceleration is positive

-none of the options are correct

-Net force applied to the object is positive

-v-velocity is changing

-acceleration in 0 m/s^s

-Net force applied to the object is zero

-Velocity is constant

-acceleration in 0 m/s^s

-Net force applied to the object is zero

Which of the following would be typical for the peak magnitude of the vertical ground reaction force (GRF) during running?

-GRF is greater than Body weight

-GRF is less than Body weight

-GRF = Body weight

GRF is greater than Body weight

A skater gliding on ice will continue to move in the same direction and with the same speed (in the absence of the action of additional forces). This exemplifies which of the following laws? 

-Newton's third law of action/reaction

-Newton's second law of acceleration

-Newton's first law of inertia

-Newton's law of gravitational force

Newton's first law of inertia

The higher the jump, the "harder" the landing. This statement reflects which of the following laws?

-Law of inertia

-Law of torque

-Law of Action-Reaction

-Law of momentum

Law of Action-Reaction

Which of the following is not true about mass? 

-all options are not true about mass

-measurement unit = kg

-affects the acceleration resulting from an applied force

-it represents quantity of matter of an object

-changes depending on gravity

changes depending on gravity

What happens to momentum when an impulse acts on a system?

-all options are correct

-momentum is changed

-momentum is conserved

-impulse does not affect momentum

momentum is changed

Which variable(s) determine the quantity of motion of an object? Select all of the options that are correct. 

-time

-mass

-velocity

-momentum

-acceleration

-Mass

-Momentum

-Velocity

What items must be included in a free body diagram of the lawn mower in the figure below? Select all options that are correct.

-the normal reaction force applied to the person

-dot, box, or sketch of the person pushing the lawn mower

-friction

-normal reaction force applied to the lawn mower

-the horizontal and vertical accelerations of the lawn mower

-dot, box, or sketch of the lawn mower

-the force applied by the person to the lawn mower

-weight of the lawn mower

-weight of the person pushing the lawn mower

-dot, box, or sketch of the lawn mower

-normal reaction force applied to the lawn mower

-the force applied by the person to the lawn mower

-weight of the lawn mower

-the horizontal and vertical accelerations of the lawn mower

-friction

Given that gravity is lower on the moon than on the earth, which of the following quantities would be different on the moon than on the earth? Select all options that are correct.

-Body Mass

-Body density

-Body weight

-The net force of the object at rest

Body weight

Elite sprinters have faster initial velocities at the start of a race than sub-elite sprinters.  True or False: One reason for these faster initial starting velocities is that elite sprinters display greater impulse against the starting blocks than sub-elite sprinters. 

-True

-False

True

Which of the following statements is true about the relationship between impact and impulse? 

-impact is always greater than impulse

-impacts generates impulses

-impulses generate impacts

A free body diagram includes which of the following? Select all options that are correct.

-vector representations of all the accelerations of the object

-sketch of an object, body, or body part being analyzed

-objects external to the system being analyzed but applying forces to the object being analyzed

-vectors representations of all forces acting on the system

-none of the options are correct

-sketch of an object, body, or body part being analyzed

-vector representations of all the accelerations of the object

-vectors representations of all forces acting on the system

When two bodies collide head-on and then continue to travel collectively in the original direction of motion of one of the bodies. What factor determines the direction of collective motion after the collision?

-Relative momentum of the two bodies

-Relative weights of the two bodies

-Relative acceleration of the two bodies

-Relative masses of the two bodies

Relative momentum of the two bodies

A cross-country skier is gliding across the snow with a constant velocity. Which of the following statement(s) is(are) true?  Select all options that are correct.

-net force in the vertical direction is zero

-mass is constant

-momentum is constant

-net force in the horizontal direction is zero

-net force in the horizontal direction is positive

-acceleration is 0

-net force in the vertical direction is 0
-net force in the horizontal direction is 0
-acceleration is 0
-mass is constant
-momentum is constant

True or False: Air resistance and friction are two common forces that act to reduce the momentum of an object.

-True

-False

True 

Which of the following relationships is always true? 

-coefficient of kinetic friction < coefficient of static friction

-coefficient of kinetic friction = coefficient of static friction

-coefficient of kinetic friction > coefficient of static friction

-None of the options are true

coefficient of kinetic friction < coefficient of static friction

Which of the following factors does not affect the amount of friction generated between two dry surfaces?

-the normal force

-the coefficient of friction between two surfaces

-the reaction force

-the surface area in contact

The surface area in contact

Which of the following relationships is correct?

-None are correct

-m= F/a

-a = m/F

-F = m/a

m=F/a

Which variable(s) determine the impulse applied to an object? Select all of the options that are correct. 

-velocity

-mass

-time

-force

-acceleration

-momentum

-Force 

-Time 

Which of the following correctly describes impact? 

-large force applied over a short period of time

-small force applied over a short period of time

-large force applied over a long period of time

-small force applied over a long period of time

 

Flag question: Question 23

Which of the following could be defined by a movement analyst as a mechanical system?

-Entire human body

-Right arm

-All of the options are correct

-Projected ball

All of the options are correct

How does adding weight to the back of a pickup truck increase the friction between the tires and the icy road?

-Friction is not increased

-it increases the normal reaction force

-it decreases the normal reaction force

-Changes coefficient of static friction

-Changes coefficient of kinetic friction

It increases the normal reaction force