Forces and Friction Problem

1
Forces and Friction Problem

• Created for CVCA Physics
• By
• Dick Heckathorn
• 14 November 2K3

2
A 25.0 kg block has been sliding on a
frictionless, horizontal ice surface at 2.00 m/s.
Suddenly it encounters a large rough patch where
the coefficient of kinetic friction is -0.05. How
far does the block travel on this rough
surface? All questions refer to the motion on
the rough surface.
3
Fice on b
Ffriction
Fe on b
1.
How many different forces are acting on the
block? Ignore air resistance.
5
0
2
3
4
1
4
Fe on b
2. What is the direction of the weight force?
F
A
C
D
E
B
5
Fice on b
3. What is the direction of the normal force?
F
A
C
D
E
B
6
Ffriction
4. What is the direction of the frictional force?
F
A
C
D
E
B
7
Fice on b
Ffriction
Fe on b
5. Is the block accelerating?
Yes
Not enough information
No
8
Fice on b
Fe on b
6. What is the acceleration in the y-direction?
gt0
Not enough information
lt0
0
9
Ffriction
7. What is the acceleration in the x-direction?
gt0
Not enough information
lt0
value in a - direction
0
10
Fice on b
Choices
Ffriction
245 N
-12.25 N
12.25 N
-245 N
(ma)x
0 N
Fe on b
x-direction
y-direction
______
______
0
-245 N
Weight Force
______
______
Normal Force
245 N
0
______
______
Friction Force
-12.25 N
0
______
______
(max)
Total Force
-12.25 N
0
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Fice on b
9. Find the x-component of the acceleration, and
use it to determine the acceleration.
Ffriction
Fe on b
acceleration
distance
__________
__________
- 0.49 m/s2
4.08 m
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Thats all folks!