Transcript Document

Ch. 4 HW
Dec 11
Fnet = ma
Weight = Fgrav = mg
1) If drag is 26,400 N and the lift is 29,300
N, determine the weight, mass and thrust,
given that the plane is traveling at a
constant velocity. What is the net force
acting on the plane?
2) If the net force acting on the plane is
9250 N to the left, and the thrust force is
35,000 N, what is the drag force? What is
the rate of acceleration?
Draw Free Body Diagrams
1.
0.5 N acorn falling to the ground with air resistance
totaling ¼ of its weight.
– What is the net force acting on the acorn? Is the acorn
accelerating? If so, at which rate?
2.
A 45 N box being pushed to the right with 35 N of force,
with a net force of 9 N to the right.
– Is the box accelerating? If so, at which rate and in which
direction?
3.
A 1.5 kg book resting horizontally on a table
4.
Draw the four forces acting on the book if it is at rest on a
15 degree slope. Fg,y = Fn = Fg cos
• Fg,x = Fg sin
represents the angle of the slope
29,300 N
26,400 N
26,400 N
m = W/g = 29,300
N/9.81 m/s2 = 2990 N
1) If drag is 26,400 N and the lift is 29,300 N,
determine the weight, mass and thrust, given
that the plane is traveling at a constant velocity.
What is the net force acting on the plane?
Net Force = 0 N
2) If the net force acting on the plane is 9250 N
to the left, and the thrust force is 35,000 N, what
is the drag force? What is the rate of
acceleration?
a = Fnet/m = 9250 N/2990 kg = 3.09 m/s2
Drag force
= 25,750 N
Free Body Diagram Practice
F air = 0.125 N
F net = .375 N
downward
Fg = 0.5 N m=w/g=
0.5/9.81 m/s2 = 0.510 kg
a = Fnet/m = 0.375N/.0510 kg
= 7.35 m/s2 downward
F norm = 40 N
F net = 9 N to
the right
a = Fnet/m = 9 N/5 kg
= 2 m/s2 to the right
F friction =
26 N
F applied =
35 N
F norm = 15 N
Fg = 40 N
m = 40 N /9.81 m/s2 = 4 kg
Fg = 15 N (w = 1.5 kg x 9.8 m/s2)
Rounded to two sig figs
Fn = 15 N
Fs = 3.9 N
Fg,x = 3.9 N
15°
Fg,y = 14 N
Fg = 15 N