Download Newton*s First Law

Question 1
• What is the SI unit of force
Answer
• Newton
Question
• What is the combination of all forces acting on
an object called?
Answer
• Net force
Question
• What is the name of the force that always
points in a direction perpendicular to the
surface of contact?
Answer
• Support (a.k.a. Normal) force
Question
• What are 2 states of motion that an object in
equilibrium might be undergoing? (1 point
each)
Answer
• At rest
• Constant speed in a straight line
Question
• Find the net force acting on the given object
FN=121N
Fapp=150 N
30°
Ff=60 N
Fg=196 N
Answer
• 70 N East
Question
• Solve for the force that would put the
following system in equilibrium?
FN= 174.3N
Fapp=100 N
45°
Ff=40 N
Fg =245 N
Answer
• 30.7 N West
Question
• A 50-N applied force (30 degrees to the horizontal) accelerates a box
across a horizontal sheet of ice (see diagram). Glen Brook, Olive N.
Glenveau, and Warren Peace are discussing the problem. Glen suggests
that the normal force is 50 N; Olive suggests that the normal force in the
diagram is 75 N; and Warren suggests that the normal force is 100 N.
While all three answers may seem reasonable, only one is correct. Who is
correct?
Answer
• Olive is correct
Question
• Find the weight of the picture.
Answer
• 42.4 N
Question
• The sign has a mass of 50 kg. Find the tension
in diagonal cable supporting the sign.
Answer
• 1000 N
Question
• The sign has a mass of 10 kg. Find the tension
in each cable.
Answer
• 57.7 N
Question
• Objects at rest are said to be in ______
equilibrium; object moving at constant speed
in a straight-line path are said to be in
________ equilibrium. (1 point each)
Answer
• Static; dynamic
Question
• What is the difference between mass and
weight?
Answer
• Weight is affected by gravity
Question
• What is the SI unit of mass?
Answer
• kilogram
Question
• What is the force that acts as resistance to
motion of objects that are in contact?
Answer
• friction
Question
• What is the property of anything to resist
changes in the state of motion?
Answer
• inertia
Question
• What is a measure of inertia?
Answer
• mass
Question
• A mother finds her newborn son weighs 300N,
a possible new world record, calculate his
mass. Round to one decimal place.
Answer
• 30 kg
Question
• When you compress a junked car into a cube,
which will change its mass, weight or volume?
Answer
• volume
Question
• You are whirling a ball tied to a string in a
circle above your head. Suddenly your friend
cuts the string. Sketch the path the ball will
take.
Answer
• Sketches will vary. Will travel in a straight line
path tangential to its previous circular path.
Question
• What does “g” represent in the equation W =
mg? (I’m going to be picky so be specific)
Answer
• Acceleration due to gravity
Question
• What are the units of “g”?
Answer
• m/s²
Question
• What is the mass of a 63 kg object on Venus
where the acceleration due to gravity is 5.8
m/s²?
Answer
• 63 kg silly!
Question
• A 5 kg object is moving with a speed of 6 m/s.
How much force is required to keep the object
moving at the same speed in the same
direction?
Answer
• No force required.
Question
• Which has a greater mass, a 2 kg pillow or a 2
kg car battery?
Answer
• Their masses are equal.
Question
• In the presence of ____________ a force is
required to keep an object moving at a
constant speed in a constant direction.
Answer
• friction
Question
• What direction does friction act?
Answer
• Parallel to the surface of contact in the
direction opposite motion.
Question
• What is the mass of a 60 N human on earth?
Answer
• 6 kg
Question
• Which has more inertia, a 100 g mass, a 200 g
mass, or a 50 g mass?
Answer
• 200 g mass
Question
• How does an object’s weight change if its
mass is doubled?
Answer
• Weight doubles also. Mass and weight are
proportional.
Question
• If you’re riding in a smooth-riding bus that is
going at 40 km/h and you flip a coin vertically,
how fast does the coin move horizontally
while in midair?
Answer
• 40 km/h
Question
• In an orbiting spacecraft, you are handed two
identical closed boxes, one filled with sand
and the other filled with feathers. How can
you tell which is which without opening it?
Answer
• Shake them. The lighter one will be easier to
shake.
• Push them. The lighter one will be easier to
push.
Question
• If a woman weighed 500 N on Earth, what
would she weigh on Jupiter, where the
acceleration of gravity is 26 m/s²
Answer
• 1300 N
Question
• Why does the acceleration due to gravity vary
among planets?
Answer
• Because planet’s masses vary and acceleration
due to gravity depends on mass.
Question
• What is the mass of a 150 lb. person? Round
to one decimal place. (1 lb = 4.6 N)
Answer
• 68.2 kg
Question
• According to newton’s first law, what is
required to change an objects state of
motion?
Answer
• A force
Question
• A 5 kg ball is taken to the moon, which will
vary the ball’s mass or the ball’s weight?
Answer
• weight
Final Jeopardy!
• A “Newton” is a derived unit, meaning that it
is simply a name given to a combination of
different units. What is a “Newton” equal to?
Answer
• Kg m
s²