Download Test 2 Review Test 2 Review_9

Test 2 Review
Physical Science
MTHS/Matthews
Name _____________________________
Directions: Answer these questions individually using your text book, your notes, old assignments and quizzes
and your own reasoning. You will receive a stamp the day that this assignment is due provided that you show
sufficient effort to complete as much of this review as possible.
Newton’s 3rd Law: Whenever one object exerts a force on a second object, the second object exerts an equal and
opposite force on the first object.
(1) Read page 373 in the textbook and describe an example from this page that demonstrates Newton’s 3rd Law.
(2) Why don’t action and reaction forces cancel? (see page 373)
(3) __________ A linebacker strikes a fullback with full force in a football game. The reaction force to the force
of the linebacker striking the fullback is ____.
a. the sound of the pads colliding
b. the force of the fullback colliding with the ground
c. the fullback fumbles
d. the fullback applies a force to the linebacker
e. the linebacker applies a force to himself
ab. the fullback applies a force to himself
ac. there is a 3-yard loss
ad. the fullback falls backwards to the ground
(4) __________ Late one night, an unfortunate bug collides with the windshield of a fast-moving bus. The force
of the bus on the bug is _____ the force of the bug on the bus; the resulting acceleration of the bug is ____ the
acceleration of the bus.
a. greater than, greater than
b. greater than, less than
c. greater than, equal to
d. equal to, equal to
e. equal to, greater than
ab. equal to, less than
ac. less than, less than
ad. less than, greater than
ae. less than, equal to
(5) __________ An apple is at rest on a table. If the action force is, Earth pulls down on Apple,
then the reaction force is:
(A) Apple pushes down on table
(B) Table pushes up on Apple
(C) Apple pulls up on Earth
(D) Apple does not move
(6) __________ The gravitational force exists between:
(A) Any two masses
(B) Two magnets
(C) The earth and objects on it.
(7) Read pages 380 & 381. Draw at least 3 examples of gravitational forces acting on different masses at
different distances. Describe how these factors affect the gravitational force.
Newton’s 2nd Law: The acceleration of an object is proportional to the net force acting on the object and
inversely proportional to its mass (ie, a = Fnet / mass).
(8) Read page 365-369 and describe an example or two from this section that explains the effect of force on
motion and the effect of mass on motion.
(9) ___________ A net force acts on an object that causes an acceleration of 4 m/s2. What acceleration will
result on the same mass if the net force is quadrupled (4 times the push)?
(10) ____________ A net force acts on an object that causes an acceleration of 4 m/s2. What acceleration will
result from the same force of F on an object with half the mass?
(11) ___________ A net force acts on an object that causes an acceleration of 4 m/s2. What acceleration will
result a push that is 3 times as hard on a mass that is 1/3rd as large?
(12) An automobile with a mass of 1000 kg accelerates when the traffic light turns green. If the applied force
acting on the car is 5000 Newtons and the car experiences 1000 Newtons of air resistance then what is the car’s
acceleration? Draw a force diagram with labels & force values & show all work and include all units.
(13) An automobile slams on the brakes and experiences a -1000 Newton frictional force that causes the car to
slow down at a rate of -0.5 m/s/s. Calculate the mass of the car? Show all work and include all units.
Directions: Use the force diagrams below in order to answer questions 14-18. YOU MAY USE MORE THAN
ONE PICK FOR EACH QUESTION AND YOU MAY USE EACH OPTION MORE THAN ONCE IF
NEEDED.
F. None of these
(14) ___________ Which diagram(s) show balanced forces?
(15) ___________ Which diagram(s) show unbalanced forces?.
(16) ____________ Which diagram(s) show an object that would speed up if the objects were moving to the right.
(17) ___________ Which diagram(s) show an object that would slow down if the objects were moving to the right
(18) __________ Which diagram(s) show an object that would move at a constant speed?
(19) A force diagram is shown at right for a skydiver moving downwards. Describe the
motion of the skydiver and explain your answer. Then find the mass acceleration of the
skydiver.
(20) Draw a force diagram for all the forces acting on each of the objects described below. For each diagram
Label ALL VERTICAL AND HORIZONTAL forces by name and write the amount of force next to ALL force
arrows in Newtons.
A 3 kg weight hanging on a spring
A 2 kg block is pulled to the right by a string with a 10
Newton Force across a table but the block does not
move.
A 40 kg appliance is pushed across the floor at a
constant speed by a 100 Newton force from a
mover.
A 1000 kg elevator being pulled up by a cable moves
upward but slows down.
A 40 kg ice skater glides to the right across a
friction free surface at a constant speed.
The 40 kg ice skater glides off of the ice onto a rough
surface where she experiences a 100 Newton frictional
force.
Newton’s 1st Law: The state of motion of an object does not change as long as the net force acting on the object
is zero.
(21) Read pages 364-365 and describe an example from the textbook that demonstrates Newton’s first Law.
(22) _________ A 4.0-kg object is moving across a frictionless surface with a constant velocity of 2 m/s. Which
one of the following horizontal forces is necessary to maintain this state of motion?
(A) 0 N
(B) 0.5 N
(C) 2.0 N
(D) 8.0 N
(E) Depends on the speed
(23) _________ The speeds and masses of four objects are given below. Which one of the following objects has
the greatest inertia?
(A) 5 kg object moving at 12 m/s
(C) 21 kg object moving at 3 m/s
(B) 12 kg object moving at 5 m/s
(D) 55 kg object which is not moving
(24)___________ If the forces acting upon an object are balanced, then the object
(A) must not be moving.
(C) must not be accelerating.
(B) must be moving with a constant speed.
(D) None of these.
(25) ___________ An air hockey puck is thrown horizontally and slides across the air hockey table (with air on)
at a constant speed. Which of the following must be true about the forces acting on the puck:
(A) There is no force to the right and the frictional force is zero or nearly zero.
(B) The force to the right is larger than the frictional force.
(C) The force of motion is proportional to the speed of the puck.
(D) The force to the right must be equal to the force from friction.
(26) ___________ True or False: A force is required to keep objects moving.
(27) Using Newton’s 1st Law, explain why it is important for students to wear seat belts. In your answer use the
terms, inertia, force, collision.
(28) Rank the following gravitational interactions from least to greatest force. If you cannot fully rank them
explain why. Bigger circles represent more mass. Explain your reasoning for your ranking.
A
B
C
D