force is a push or pull while a net force is the combination of all acting forces
what is the difference between force and net force on an object
tension
what name is given to the stretching force that occurs in a spring or rope being pulled
magnitude and direction
what two quantities are necessary to determine a vector quantity
vector quantity needs both magnitude and direction while scalar quantity needs only magnitude
how does a vector quantity differ from a scalar quantity
force
give an example of a vector quantity
time, area, or volume
give an example of a scalar quantity
20 N
how much tension is in a rope that holds up a 20 N bag of apples at rest
net force is 10 N to the right
what is the net force on a box that is being pulled to the right with a force of 40 N and pulled to the left force of 30 N
the vector sum of all the forces that act on an object equal zero
what is the net force on an object at rest
each arm supports half your weight
when you do pull-ups and you hang at rest, how much of your weight is supported by each arm
90 degrees
support force is perpendicular to the surface
support force is perpendicular to the surface
what is the angle between a support force and the surface an object rests upon
support (normal) force and gravity (weight)
what two forces compress a spring inside a weighing scale when you weigh yourself
the sum will equal your weight when you are at rest
when you are at rest and supported by a pair of weighing scales, how does the sum of the scale reading compare with your weight
yes – if it moves at constant speed in a straight line
can an object be moving and still be in equilibrium? defend your answer
both forces are equal in magnitude, but in opposite directions
the net force is zero
if you push a crate across a factory floor at constant speed in a constant direction, what is the magnitude force of friction on the crate compare with your push
static – rest
dynamic – constant speed in a straight line
dynamic – constant speed in a straight line
distinguish between static equilibrium and dynamic equilibrium
resultant – the sum of the two vectors
according to the parallelogram rule for two vectors, what does the diagonal of a constructed parallelogram represent
downward force is weight
two upward forces are tension in rope
two upward forces are tension in rope
consider the suspension of Nellie in Figure 2.11 (pg 21). Name the three forces that act oh her. What is evidence that they cancel to zero
rope tensions are greater
consider Nellie in Figure 2.12 What changes in rope tension occur when ropes make a grater angle with the vertical
resultant of both rope tensions is equal in magnitude and opposite in direction to the vector representing her weight
when Nellie hangs from ropes at different angles as shown in Figure 2.13 how does the vector resultant of the two rope tensions compare with her weight
