KPE160 DOUG PREP STUDY GUIDE
Centre of Gravity vs Centre of Mass - Answer -centre of mass depends on the
distribution of mass (not gravitational field) and it doesn't change even if you move or
orient yourself differently. Centre of gravity is a unique point which weight is balanced, it
can change based on orientation and also takes into account mass distribution.
Is it harder to lift or lower a mass? Which feels harder and why? - Answer -It takes the
same amount of force. When you're applying a force greater than the weight its going to
accelerate up, if you apply less it will accelerate downwards. If you lower or raise the
mass with constant velocity you are applying exactly the weight of the mass to cancel
out gravity. You are not stopping the object, it simply prevents it from accelerating. It
feels harder to lift the mass because your brain has to activate your muscles more.
(force-velocity relationship in muscle)
does being flexible prevent injury? - Answer -flexible people get injured more often.
flexibility is important for performance (not health). range of motion makes your muscles
faster (speed comes from having long muscles).
How long does it take for a fastball thrown at 48 m/s to get to home plate 18.44 m
away? - Answer -0.38s
Mass vs weight - Answer -Mass is a measurement of the amount of matter something
contains, while Weight is the measurement of the pull of gravity on an object.
Moment of force - Answer -M = F * d (perpendicular distance from line of action to the
axis of rotation). The moment of force about a point or axis is a measure of its tendency
to cause rotation about that point or axis
momentum vs impulse - Answer -They represent different aspects of motion.
Momentum describes how hard it is to stop an object from moving, it depends on
inertia(mass) and velocity(speed). Whereas impulse describes the change in
momentum which results from application of force over time.
basics - explain these terms and their relations to another: mass, energy, force, work,
power - Answer -mass: amount of matter
energy: capacity to do work (joules)
force: accelerating a mass (newton)
work: applying a force to an object over a distance
power: how fast you do work (watts: joules/sec)
what is kinetic potential, gravitational potential, and elastic potential energy - Answer -
kinetic: energy stored in a moving body (collisions). the faster you're moving the more
kinetic energy you have
gravitational: energy stored by an elevated body, capacity to do work by falling
, elastic: energy stored in an elastically-deformed body, capacity to do work by returning
to neutral shape
What are two things you can change to increase your power? - Answer -P = work/ time
= force(strength) * velocity(speed
units for acceleration - Answer -m/s^2
units for energy and work - Answer -Joules
units for moment of inertia (Not sure if right) - Answer -M = N * m
kgm^2
units of force - Answer -Newtons
Base unit of the newton - Answer -F=m * a
N=(Kg)(m/s^2)
Base units of a Joule - Answer -kgm^2/s^2
units for power - Answer -Watts
Base Unit- Watt - Answer -kg*m^2/s^3 (joules/second)
what unit is a newton-metre - Answer -joule
what do you multiply m/s by to convert to km/h - Answer -3.6 !
what is the term for agent of energy transfer between bodies? - Answer -force
what is the term for energy transfer between bodies - Answer -work
why do things fall at the same time if we ignore air resistance? - Answer -heavier
objects have more inertia
what is inertia - Answer -property of matter that resists acceleration (objects don't want
to change their velocity)
what is newtons first law of inertia - Answer -inertia resists acceleration. moving objects
keep moving, stationary objects stay stationary.
what is newtons second law of acceleration - Answer -acceleration proportional to
unbalanced external load and inversely proportional to its inertia(mass). F = ma
Centre of Gravity vs Centre of Mass - Answer -centre of mass depends on the
distribution of mass (not gravitational field) and it doesn't change even if you move or
orient yourself differently. Centre of gravity is a unique point which weight is balanced, it
can change based on orientation and also takes into account mass distribution.
Is it harder to lift or lower a mass? Which feels harder and why? - Answer -It takes the
same amount of force. When you're applying a force greater than the weight its going to
accelerate up, if you apply less it will accelerate downwards. If you lower or raise the
mass with constant velocity you are applying exactly the weight of the mass to cancel
out gravity. You are not stopping the object, it simply prevents it from accelerating. It
feels harder to lift the mass because your brain has to activate your muscles more.
(force-velocity relationship in muscle)
does being flexible prevent injury? - Answer -flexible people get injured more often.
flexibility is important for performance (not health). range of motion makes your muscles
faster (speed comes from having long muscles).
How long does it take for a fastball thrown at 48 m/s to get to home plate 18.44 m
away? - Answer -0.38s
Mass vs weight - Answer -Mass is a measurement of the amount of matter something
contains, while Weight is the measurement of the pull of gravity on an object.
Moment of force - Answer -M = F * d (perpendicular distance from line of action to the
axis of rotation). The moment of force about a point or axis is a measure of its tendency
to cause rotation about that point or axis
momentum vs impulse - Answer -They represent different aspects of motion.
Momentum describes how hard it is to stop an object from moving, it depends on
inertia(mass) and velocity(speed). Whereas impulse describes the change in
momentum which results from application of force over time.
basics - explain these terms and their relations to another: mass, energy, force, work,
power - Answer -mass: amount of matter
energy: capacity to do work (joules)
force: accelerating a mass (newton)
work: applying a force to an object over a distance
power: how fast you do work (watts: joules/sec)
what is kinetic potential, gravitational potential, and elastic potential energy - Answer -
kinetic: energy stored in a moving body (collisions). the faster you're moving the more
kinetic energy you have
gravitational: energy stored by an elevated body, capacity to do work by falling
, elastic: energy stored in an elastically-deformed body, capacity to do work by returning
to neutral shape
What are two things you can change to increase your power? - Answer -P = work/ time
= force(strength) * velocity(speed
units for acceleration - Answer -m/s^2
units for energy and work - Answer -Joules
units for moment of inertia (Not sure if right) - Answer -M = N * m
kgm^2
units of force - Answer -Newtons
Base unit of the newton - Answer -F=m * a
N=(Kg)(m/s^2)
Base units of a Joule - Answer -kgm^2/s^2
units for power - Answer -Watts
Base Unit- Watt - Answer -kg*m^2/s^3 (joules/second)
what unit is a newton-metre - Answer -joule
what do you multiply m/s by to convert to km/h - Answer -3.6 !
what is the term for agent of energy transfer between bodies? - Answer -force
what is the term for energy transfer between bodies - Answer -work
why do things fall at the same time if we ignore air resistance? - Answer -heavier
objects have more inertia
what is inertia - Answer -property of matter that resists acceleration (objects don't want
to change their velocity)
what is newtons first law of inertia - Answer -inertia resists acceleration. moving objects
keep moving, stationary objects stay stationary.
what is newtons second law of acceleration - Answer -acceleration proportional to
unbalanced external load and inversely proportional to its inertia(mass). F = ma
