This applet shows the free-body diagram of an object on an incline that is subject to a friction force. It does not show motion of the object the way the above applet did in the lecture video.
PoP5 4.27b
A car's accelerometer (consisting of a mass on a string) hangs θ = 23.0° from the vertical. What is the car's acceleration?
A. 3.83 m/s2
B. 4.16 m/s2
C. 15.6 m/s2
D. 23.1 m/s2 Answer
PoP5 4.18 mod
A sea lion slides from rest down a frictionless 15.0° ramp that is 2.00 m long. What is its speed at the bottom?
A. 0.536 m/s
B. 0.163 m/s
C. 6.26 m/s
D. 3.19 m/s Answer
HRW10e 5.87mod
When a person stands on a scale in an elevator that is at rest, the scale reads 755 N. What does the scale read when the elevator accelerates downward at 2.20 m/s²?
A. 169 N
B. 585 N
C. 755 N
D. 924 N Answer
klm
A 4.54-kg bag of French fries (?) hangs from a clothesline, each side of which makes an angle θ = 15.0° from the horizontal. What is the tension in the clothesline?
A. 11.5 N
B. 44.5 N
C. 86.0 N
D. 332 N Answer
PoP5 4.26b
A 10.0-kg load is suspended by three cords as shown. What is the tension in the strand of cord labeled
T1?
A. 98.0 N
B. 113 N
C. 196 N
D. 339 N Answer
wk4
Two canoes meet in the middle of a lake. After a brief visit, a person in canoe 1
(m1 = 100 kg) pushes on canoe 2 (m2 = 200 kg)
and in turn gets pushed. How are the magnitudes of the two forces related?
A. F1 = F2
B. F1 = ½F2
C. F1 = 2F2
D. F1 = 4F2 Answer
PoP5 4.36
Two masses of m1=11.0 kg and m2=16.0 kg are connected as shown.
What will their acceleration be? See also the interactive applet.
A. 3.06 m/s2
B. 0.265 m/s2
C. 1.81 m/s2
D. 9.80 m/s2 Answer
answer
B. 585 N
The person's mass is m = W/g = (755 N)/(9.80 m/s²) = 77.0 kg, and the scale reads the amount of the normal force acting on the person.
Newton's second law (in the vertical direction) for the person reads +FN −mg = ma. Hence the scale will read: FN = ma + mg = (77.0 kg)(−2.20 m/s² + 9.80 m/s²) = 585 N