Chapter 8 Questions Flashcards
Which has a greater momentum: heavy truck at rest or a moving skateboard?
the moving skateboard has a greater momentum because it is moving
what are two ways to increase input?
increasing the force or increasing time of appplication
how is the impluse-momentum relationhsup related to newtons second law
it is derived from it
why is it advantageous to roll with the punch in boxing?
the impact occurs over a long time
when you are struck by a moving object, is it favorable that the object makes contact for short or long period of time?
less force occurs if momentum is decreased over a long time
what case requires the greatest impulse?
a basketball that is caught then thrown back
after the collision, Car A is at rest. How does the speed of Car B compare with the intial speed
car b has the speed of car a before the collision
is it correct to say that if no net impulse is exerted on a system, then no change in the momentum of the system will occur
yes
when a cannon ball is fired, momentum is conserved for the system cannon+ cannonball. Would momentum be conserved for the systme if momentum were not a vector quanitiy
no
which has the greater momentum when moving
a container ship
which of the following has the largest momentum relative to the earth’s surface
pick up truck speeding along a highway, inerita in action has to be moving
a car traveling along the highway brakes to a stop over a certain distance. more braking force is required if the car has
more mass, more momentum, less stopping distance
airbags in cars increase safety in the event of an accident because passengers hitting the inflated airbag encounter a
lengthened time of contact
two identical gliders slide toward each other on an air track. One moves at 1 m/s and the other at 2 m/s. They collide, stick, and move together
1/2 ms
a 5000-kg freight car moving 2 m/s collides with a 10000-kg freight car at rest. They couple upon collision and move away at
2/3 m/s
a motorcycle of mass 100 kg slowly rolls of the edge of a cliff and falls for three seconds before reaching the bottom of a gully. Its momentum upon hitting the ground is
3,000 kg-m/s
3(10g)= 30
100(30)
3000
airbags in cars increase safety in the event of an accident because passengers hitting the inflated airbag encounter an
lenghtned time of contact
A 5000-kg freight car collides with a 10,000-kg freight car at rest. They couple upon collision and move at 2 m/s. What was the initial speed of the 5000-kg car?
6 m/s
Pi=Pf
