Transcript Slide 1 - Cloudfront.net

(Mon) A 10-newton force and a 15-newton force are
acting from a single point in opposite directions. What
additional force must be added to balance the forces?
(5 min / 5 pts)
(Mon) A 10-newton force and a 15-newton force are
acting from a single point in opposite directions. What
additional force must be added to balance the forces?
(5 min / 5 pts)
10 N
15 N
Balanced Forces: Fnet = 0
F1 = -10 N
F2 = +15 N
Fnet = 0 = F1 + F2 + F3
0 = (-10 N) + (15 N) + F3
0 = (5 N) + F3
F3 = -5 N
(Tue) The figure shows a block that is being pulled along
the floor. According to the figure, what is the acceleration
of the block? (5 min / 5 pts)
(Tue) The figure shows a block that is being pulled along
the floor. According to the figure, what is the acceleration
of the block? (5 min / 5 pts)
Fnet = ma
Or a = (Fnet)/(m)
Fnet = Ff + Fpull
Fnet = (-10 N) + (50 N)
Fnet = 40 N
a = 40 N / 20 kg
a = 2 m/s²
(Wed) The figure shows a block that is being pulled
along the floor. According to the figure, what is the
kinetic coefficient of friction between the block and the
floor? (5 min / 5 pts)
(Wed) The figure shows a block that is being pulled
along the floor. According to the figure, what is the
kinetic coefficient of friction between the block and the
floor? (5 min / 5 pts)
FF = μkFN
FF / FN = μk
FN = Fg
Fg = (m)(ag)
Fg = (20 kg)(9.81 m/s²)
Fg = 196.2 N = FN
FF / FN = μk = 10 N / 196.2 N
μk = 0.051 (no units)
(Thu) Teacher is off on a Field Trip – No warm up today
(Fri) The figure shows a block that is being pulled along
the floor. According to the figure, what is the velocity of
the block after pulling with a constant force for 10
seconds? (5 min / 5 pts)
(Fri) The figure shows a block that is being pulled along
the floor. According to the figure, what is the velocity of
the block after pulling with a constant force for 10
seconds? (5 min / 5 pts)
F = ma
FNet = (FF) + (Fpull) = 40 N (to the right)
a = F/m = 40 N / 20 kg = 2 m/s² (to the right)
Assume: initial velocity = 0 m/s
vf = vi + at
vf = 0 m/s + (2 m/s²)(10 s)
vf = 20 m/s
End of Week Procedures:
1. Add up all the points you got this
week
2. Put the total number of points at the
top of your page (out of 20 points)
3. List any dates you were absent (and
why)
4. Make sure your name and period is
on the top of the paper
5. Turn in your papers