Newton’s Laws review 2
Name________________
Date________
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1. Consider the free-body diagram shown at the right. Use the
numerical value for the individual forces and the approximate value
of g (10 m/s/s) to determine the acceleration of the object (in units
of m/s/s). Assign a negative number to the acceleration if it is
leftward or downward. (-5m/s/s)
2. Consider the free-body diagram shown at the right. Use the numerical
value for the individual forces and the approximate value of g (10
m/s/s) to determine the acceleration of the object (in units of m/s/s).
Assign a negative number to the acceleration if it is leftward or
downward. (4m/s/s)
3. A 50-Newton rightward force is applied to a 20-kg object to accelerate it to the right. The object
encounters a friction force of 30 Newton.
Fill in all blanks in the diagram and determine the magnitude of the acceleration (in m/s/s)
of the object. (Use the approximation that g ~ 10 m/s/s.) Enter positive numbers only.
Newton’s Laws review 2
Name________________
Date________
_____________________________________________________________________________________
4. The cable of a freight elevator applies a 2300-N force to accelerate a 200-kg elevator
upward.
Fill in all blanks in the diagram and determine the magnitude of the acceleration (in m/s/s)
of the elevator. (Use the approximation that g ~ 10 m/s/s.) Enter positive numbers only.
5. A 1200-kg rightward-moving car encounters 8400-N of resistive forces as it skids to a stop.
Fill in all blanks in the diagram and determine the magnitude of the acceleration (in m/s/s) of the
car. (Use the approximation that g ~ 10 m/s/s.) Enter positive numbers only.
Newton’s Laws review 2
Name________________
Date________
_____________________________________________________________________________________
6. Which of the following free-body diagrams would be characteristic of an object that has reached
terminal velocity?
7. An object with mass= 10.5 kg accelerates across a surface at a rate of 0.5 rn/s/s. If the force
of friction is 6.0 N, what is the force applied to the object to make it move? (11.25N)
8. If you applied a force of 200 N to push a box along the floor at a constant velocity, what is
the net force on the box? What is the force of friction on the box? (0, 200N)
9. If the net force on an object is 75 N and a force of 100 N is applied to push the object across
a table, what is the force of friction acting on the object? If the mass of the object is 5.0 kg,
what is the coefficient of friction?
( 25N, 0.5)
10. Two men are arguing over where to put a large container (mass= 250 kg).
One man pushes with a force of 400 N in one direction while the other man
pushes with a force of 600 N in the other direction. If the coefficient of
friction is 0.04, what is the net force on the object? What is the acceleration
of the object? (100N, 0.4m/s/s)
Newton’s Laws review 2
Name________________
Date________
_____________________________________________________________________________________
11. A car is traveling at 50 m/s when it slams on the brakes. How long is the skid mark if
the coefficient of friction is 0.62? (206m)
12. A boy is pushing a 50 kg sled across a frozen pond with a 100 N force as shown. If the
coefficient of friction between sled and ice surface is 0.1, what will be the acceleration of
the sled? (0.63 m/s/s left)
13. A boy is pulling a 50 kg sled across a frozen pond with a 100 N force in order to keep
the sled with constant velocity. How much is the friction between sled and ice? What is
the coefficient of friction between sled and ice surface? (86.6N, 0.19)