The Meaning of Force
Describe the two categories of forces-
What is a Newton?
Different masses are hung on a spring scale calibrated in newtons, fill in the missing value.
a) The force exerted by gravity on 1 kg = 9.8 N.
b) The force exerted by gravity on 5 kg = ______ N.
c) The force exerted by gravity on _______ kg = 98 N.
d) The force exerted by gravity on 70 kg = ________ N.
List and describe the seven of forces listed-
Use the following link to calculate your weight on different planets and moons. Answer the
questions.
http://www.exploratorium.edu/ronh/weight/index.html
Which planet gives you the closest mass to the earth?
Which celestial body would you have the least weight?
Which celestial body would you have the least mass?
Which celestial body would you have the most weight?
Which celestial body would you have the most mass?
Give your explanation of the difference between weight and mass-
Drawing free body diagrams(You will be tested on this skill so make sure that you have a solid understanding of this
process)
Apply the method described on the website to construct free-body diagrams for the situations
described below. Answers can be seen online, but try to do the assignments yourself first.
1. A book is at rest on a table top. Diagram the forces acting on the book.
2. A girl is suspended motionless from a bar which hangs from the ceiling by two ropes. Diagram
the forces acting on the girl.
3. An egg is free-falling from a nest in a tree. Neglect air resistance. Diagram the forces acting on
the egg as it falls.
4. A flying squirrel is gliding (no wing flaps) from a tree to the ground at constant velocity.
Consider air resistance. Diagram the forces acting on the squirrel.
5. A rightward force is applied to a book in order to move it across a desk with a rightward
acceleration. Consider frictional forces. Neglect air resistance. Diagram the forces acting on the
book.
Additional practice can be found on the site.
Determining the net forceFree-body diagrams for four situations are shown below. For each situation, determine the net
force acting upon the object.