Download Newton`s Laws, Numbers 1 and 2

NAME:
Force diagrams, FRICTION
Answer all questions in complete sentences, show all work were necessary, and circle all final answers in significant
figures, if appropriate.
1. What must be done to overcome inertia?
2. Force is described as a vector quantity. Explain why this is the case.
3. If the net force on an object is zero N, is the object at rest? Why or why not?
True-False: indicate whether or not the statement is true or false (write the word true, or the word false on your
paper). If the statement is false, correct it by rewriting the statement to make it a true statement.
____4. A baseball player sliding into first base will continue to move past the base with a
constant velocity if friction is disregarded.
____5. . A bowling ball has more inertia than a tennis ball. Therefore, it takes less force to
move the bowling ball than the tennis ball.
____6. A constant net force on an object will cause the object to move with a constant
velocity.
____7. A net positive force acting on an object will cause will cause the object to change its
course and/or velocity.
____8. Forces that are equal in amount and opposite in direction are unbalanced and will
cause motion to occur.
____9. In the absence of air resistance, a penny and a feather dropped from the same height,
at the same time, will hit the ground at the same time, after falling with the same
acceleration.
___10. Gravity is the tendency of an object to remain at rest.
___11. An object rolling across the floor without any horizontal force applied will slow down
due to natural external forces.
___12. Newton’s second law of motion can be expressed by the formula, a = F/m.
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Problems:
F=m·a
w=m·g
1.0 kg = 2.2 lbs
9.81N = 1.0 kg
µ=Ff/FN
13. Megan, a ballet dancer, has a mass of 45.0 kg. A). What is Megan’s weight on Earth?
B). What is Megan’s mass on Jupiter, where gravity is 25.0 m/s2? C). What is Megan’s weight on Jupiter?
14. Lopez stubs his toe on the coffee table with a force of 100. N. What is the acceleration of Lopez’s 1.80 kg foot?
15. The net external force on the propeller of a 750.g model air-plane is 17 N. What is the acceleration of the model plane?
16. A ball pushed with a force of 13.5 N accelerates at 650 cm/s2. What is the mass of the ball?
17. A 175.0 pound bald man falls through the air and encounters 12.3 N of air resistance.
a. Draw the force diagram.
b.
What is the NET force on him as he falls?
c.
What is the acceleration of the man?
18. For maximum range of a projectile, the best angle of launch is ______________________________ .
19.
A large box is being dragged across the floor at constant velocity. If the box has a mass of 50.0 kg and it takes a 60.0 N
force, acting horizontally, to drag the box, what is the coefficient of friction?
20. How much force is needed to pull a 969 N object across a level surface at constant velocity if the coefficient of friction is
0.40?
21. The coefficient of friction between a cabinet and a floor is 0.350. It takes a force of 385 N to slide the cabinet across the
room at a constant rate. What is the mass of the cabinet in kilograms?
22. You would expect the  of a rubber shoe sole on concrete to be _______ (greater than, less than, equal to ) the  of ice on ice.
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