Transcript Newtons Law Reveiw questions

Consider a ball at rest in the
middle of a wagon. When the
wagon is pulled forward the ball
begins to roll against the back
of the wagon. Interpret this
observation in terms of
Newton’s first Law.
When do you lurch forward in a bus
that suddenly slows? Why do you
lurch backward when it picks up
speed? What law applies here?
Push a shopping cart and it
moves. When you stop pushing,
it comes to a rest. Does this
violate Newton’s Law of inertia?
When a car moves along the
highway at constant velocity, the
net force on it is zero. Why, then,
do you continue running your
engine?
Roll a bowling ball down a lane
and you’ll find it moves slightly
slower with time. Does this
violate Newton’s law of inertia?
Consider a pair of forces, one
having a magnitude of 20N, and
the other is 12N. What maximum
net force is possible for these two
forces? What is the minimum
new force possible?
As you stand at rest on a floor,
does the floor exert an upward
force against your feet? If so
what exactly is this force?
A child learns in school that the
Earth is traveling faster than
100,000 KM per hour around the
sun, and in a frightened tone asks
why we aren't swept off. What is
your explanation?
If you toss a coin straight upward
while riding a train, where does
this coin land when the motion of
the train is uniform along a
straight line track? When the
train slows while the coin is in
the air? When the train is
turning?
Find the net force produced by a
30 N and 20 N force in each of
the following cases:
A: Both forces act in the same
direction.
B: Both Forces act in the
opposite direction.
What is the net force on a bright
red Mercedes convertible
traveling along a straight road at
the steady speed of 100 km/hr?
On a long alley a bowling ball
slows down as it rolls. Is any
horizontal force acting on the
ball? How do you know?
What happens to your weight
when your mass increases?
When a junked car is crushed
into a compact cube, does its
mass change? Its weight? Its
Volume? Explain….
Two basketballs are dropped
from a high building through the
air. One ball is hollow and the
other filled with rocks. Which
accelerates more? Defend your
answer...
Why will a sheet of paper fall
slower than one that is wadded
into a ball?
For each of the following
interactions, identify action and
reaction forces.(a) A hammer hits
a nail. (b)Earth gravity pulls
down on you. (c ) A helicopter
blade pushes air downward.
You hold an apple over your
head. (a) Identify all the forces
acting on the apple and their
reaction forces. (b) When you
drop the apple, identify all the
forces acting on its as it falls and
the corresponding reaction
forces.
Identify the action-reaction pairs
of forces for the following
situations:
(a) You step off a curb.
(b) You pat your tutor on the
back.
(c ) A wave hits a rocky shore.
When you drop a rubber ball on
the floor it bounces almost to its
original height. What causes the
ball to bounce?
If a massive truck and a small
sprits car have a head on
collision, upon which vehicle is
the impact force greater? Which
vehicle experiences the greater
acceleration? Explain….
If you were in a smooth riding
bus that is going 50 km/hr and
you flip a coin vertically, what is
the horizontal velocity of the coin
in midair?
Suppose you exert a horizontal
push on a crate that rests on a
level floor, and it doesn’t move.
How much friction acts
compared with your push?
What is meant by the term “Free
Fall”?
If the net force is acting on a
sliding object triples. What
happens to the acceleration?
If the mass of a sliding object
triples at the same time the net
force on it triples how does the
acceleration compare to its
original acceleration?
When only a pair of equal and
opposite forces act on an object,
what is the net force acting on it?
Which is the most important in
winning a tug-o-war;Pulling
harder on the rope, or pushing
harder on the floor?
How does a helicopter get its
lifting force?