Download Here are most of the warm-ups

Journal Entry #5 = work for Friction WA #s 4 and 5
Warm-up: 12/14/15 (#6)
Jane and John, with masses of 50 kg and 60 kg,
respectively, stand on a frictionless surface 10 m apart.
John pulls on a rope that connects him to Jane, giving
Jane an acceleration of 0.92 m/s2 toward him.
(a) What is John's acceleration?
(b) If the pulling force is applied constantly, how far from
John's starting position will they meet?
Warm-up: 12.15.15 (#7)
A large (75.0 kg) crate first starts sliding down a ramp when the
ramp makes an angle of 37° with the horizontal.
a) Draw a free-body diagram for the crate
b) What is the coefficient of static friction between the crate
and the ramp?
c) What is the acceleration of the crate if the angle is not
changed? (coefficient of dynamic friction is 0.55)
d) If the coefficient of dynamic friction is 0.55, what angle will
allow the box to slide at a constant velocity?
Warm-up 12.16.15 (#8)
The coefficients of static and kinetic friction between a 33 kg
box and a horizontal surface are 0.74 and 0.17, respectively.
(a) What is the acceleration of the object if a 345 N horizontal
force is applied to the box?
(b) What is the acceleration if the applied force is 450 N
Warm-up: 1.4.16 (#9)
Remind yourself of all the topics we have been
covering in this class in the past several weeks
(i.e. since Thanksgiving-ish)
Warm-up: 1.5.16 (#10)
A cabinet door is open, and you don’t want to
stand up to close it. You do, however, have a
tennis ball and a ball of clay near you. You
choose to throw one of them at the door (they
have the same mass). The tennis ball will
bounce off the door (but not back to you), and
the clay will stick to it before falling off. Which
would you choose as being the most likely to
close the door? Why?
Warm-up #11 is in the Momentum/Impulse
Notes
Warm-up #12 is the Frog Physics lab
Warm-up #13 is in the Momentum/Impulse
notes (What is momentum?)
Warm-up #14:
How did you collect frog lab data? What is the
momentum of the frog? Would the impulse
felt by the frog be affected by a stronger
spring? How would this impact the momentum
change of the frog?
Warm-up #15: (1/8/16)
Video notes on the Modern Marvels Crashes
video (green worksheet)—excused from this
one if you were at DECA and/or had an excused
absence.
Warm-up #16: 1/11/16
A 13.0 g bullet, traveling at 235 m/s, penetrates
a wall and emerges with a velocity of 175 m/s.
- What force has been exerted by the wall on
the bullet if it passed through the wall in
25.0 ms?
- What Impulse will stop the bullet after it
leaves the wall?
Warm-up 1.12.16 (#17)
 Define Impulse
 If a 1250 kg car traveling at 15.5 m·s-1 is
stopped in 0.750 s, what stopping force
must have been applied?
 Sketch a Force-Time graph illustrating the
stopping of the car
Warm-up: 1/13/16 (#18)
During a crash test, a 1250 kg car traveling at
25.5 m·s-1 hits a wall and comes to a stop in
0.0763 s. What is the average net force acting
on the car to bring it to a stop?
Assume the second crash test (involving the
same type of car) has the car initially traveling
at 18.0 m·s-1, but the car experiences the same
average net force through a time of 0.0675 s.
What is the final velocity of this car?