Etkina Chapter 5 (Momentum)

Question 1

Isolated system: a group of objects that interact with each other but not with ….. the system

Answer 1

external objects outside

Question 2

mass of an isolated system is the …. of the …. of all objects in the system

Answer 2

sum; masses

Question 3

law of constancy of mass: when a system of objects is isolated (a .. container), its mass equals the …. of its components and does not … — it remains constant in ….

Answer 3

closed; sum of the masses; change; time

Question 4

In an open system, change of mass can occur according to this equation: … of system at earlier …. + …. entering or leaving system between the two …. = …. of system at later ….

Answer 4

initial mass; clock reading; new mass; clock readings; final mass; clock reading

Question 5

mass is a …. quantity → such a quantity is … in an isolated system

Answer 5

conserved; constant

Question 6

the linear momentum of a single object is the product of its … and ….: p =

Answer 6

mass; velocity; m*v

Question 7

Vector quantity of momentum is in the same direction as the object’s ….

Answer 7

velocity

Question 8

SI unit of momentum is

Answer 8

kg *m/s

Question 9

total linear momentum of a system containing multiple objects is the … of the … of the individual objects

Answer 9

vector sum; momenta

Question 10

because momentum depends on the velocity of the object, and the velocity depends on choice of …., so different observers will …. for the same object

Answer 10

reference frame; measure different momenta

Question 11

the momentum of an isolated system is …. For an isolated two-object system: m1vi,1 + m2vi,2 =

Answer 11

constant; m1vf,1 + m2vf,2

Question 12

momentum of an isolated system can be split into

Answer 12

components

Question 13

both force and time interval affect momentum– the longer the time interval, the greater the ….. A small force exerted for a long time interval can change the momentum of an object by …. amount as a large force exerted for a short time interval

Answer 13

momentum change; the same

Question 14

force * time gives us the … of the external force exerted on an object

Answer 14

impulse

Question 15

the …. under a force-time graph represents impulse

Answer 15

shaded area

Question 16

we can estimate impulse by drawing a horizontal line that is approximately the …. exerted during the time interval of the impulse

Answer 16

average force

Question 17

impulse is a …. quantity that points in the direction of the …

Answer 17

vector; force

Question 18

SI unit for impulse is … = ….

Answer 18

N*s = kg * m/s

Question 19

impulse =

Answer 19

change in momentum

Question 20

if several external objects exert forces on a single-object system during a time interval, the sum of their impulses causes a …. of the system object: pf - pi = …. = …

Answer 20

change in momentum; sigma J = sigma F on system (tf - ti)

Question 21

if the magnitude of the force changes during the time interval considered in the process, we use

Answer 21

average force

Question 22

if the same amount of force is exerted for the same time interval on a large-mass object and on a small-mass object, the objects will have an equal …. because the same …. was exerted on them → BUT, the small-mass object would have a greater ….

Answer 22

change in momentum; impulse; change in velocity

Question 23

the change in momentum of a system is equal to the

Answer 23

net external impulse exerted on it

Question 24

generalized impulse-momentum principle: for a system containing 1+ objects, initial momentum plus sum of … equals the … (law of …)

Answer 24

impulses; final momentum; momentum conservation

Question 25

the length of the bars are qualitative indicators of the relative magnitudes of

Answer 25

momenta

Question 26

sum of the heights of the bars on the left plus the height of the impulse bar should equal the sum of the heights of the bars on the right to reflect

Answer 26

conservation of momentum

Question 27

when a system object collides with another object and stops, the system object travels what is called its …. By estimating …., we can estimate the ….

Answer 27

stopping distance; stopping distance; stopping time interval