Download Up/down acceleration

Up Down Acceleration
Motion on a plane with some
friction.
A box is sliding up an inclined rough plane (some friction acts).
Draw a force diagram for the box while sliding upwards (after a
brief push).
velocity
A box is sliding up an inclined rough plane (some friction acts).
Draw a force diagram for the box while sliding upwards (after a
brief push).
velocity
Normal
Force
f
mg
A box is sliding up (after a brief push) an inclined rough plane
(incline angle 25 degrees). The box has mass M = 10kg. Friction f
= 30N. Calculate the magnitude and direction of the acceleration
of the box.
y
x
Normal
Force
wx
f
wy
q
velocity
Moving Up Rough Incline
F
x
 mg sin q  30  max
10 g sin 25  30  10ax
10 g sin 25  30
ax 
10
 7.1m / s / s
A box sliding down an inclined rough plane (incline angle 25
degrees). The box has mass M = 10kg. Friction f = 30N. Calculate
the magnitude and direction of the acceleration of the box.
y
x
Normal
Force
wx
f
wy
q
velocity
Moving Down Rough Incline
F
x
 mg sin q  30  max
10 g sin 25  30  10ax
10 g sin 25  30
ax 
10
 1.1m / s / s
Difference in Accelerations
mg sin q  f
a 
m
mg sin q  f
down
ax 
m
up
x
a a
up
x
down
x
a a
up
x
down
x
mg sin q  f mg sin q  f


m
m
2f
2 mg cos q


m
m
 2 g cos q
Real Data: Cypress 9/7/10
Track angle: 5 degrees
Representative data:
a(up) = 0.8743 m/s/s
a(down) = 0.8232 m/s/s
Average difference in acceleration: 0.0549 m/s/s
a xup  a xdown  2g cos q
a a

2g cos q
up
x
down
x
0.0549

2 g cos 5
 0.0028