exam1
Place a book that weighs 10 N on a horizontal surface and the support force on the book is
10 N
the force of friction on a sliding object is 10 N the applied force needed to maintain a constant velocity is
10 N
If a freely falling object were somehow equipped with a speedometer, its speed reading would increase each second by
10 m/s
the gain is speed each second for a freely falling object is about
10 m/s
when a falling object gains 10 m/s each second, its acceleration is
10 m/s/s
a 1-kg mass at earth's surface weighs about
10N
Fido weighs 120 N and carries Trixie who weighs 40 N on her back. The support force on Fido's feet is
160 N
You're driving in a car at 50 km/h and bump into a car ahead traveling at 48 km/h in the same direction. The speed of impact is
2 km/hr
a 3000 N bear grasping a verticle tree slides down at constant velocity the friction between the tree and the bear is
3000 N
If a Jaguar sports car accelerates from zero to 100 km/h in 3.0 s its acceleration is
33.3 km/h/s
the average speed of a deer traveling a distance of 2 km in a time of one- half hour is
4 km/hr
If a ball rolls down an inclined plane and picks up 4 m/s each second it rolls, its acceleration is
4 m/s/s
Burl and paul have a total weight of 1300 N the tensions in the ropes that support the scaffold they stand on adds to 1700 N the weight of the scaffold itself must be
400 N
in a dream you're in a car traveling 50 km/hr and bump into another car traveling toward you at 48 km/h the speed of impact is
98 km/h
which has the greatest mass?
automobile battery
when sign painter burl and paul stand on opposite ends of a scaffold, the tensions in each of the two supporting ropes
depend on the relative weights of burl and paul
A kilogram is a measure of an object's
mass
your weight is
the gravitational attraction between you and the earth
a 50 N object falling in air experiences 50 N of air resistance. the amount of net force on the falling object is
0 N
An object travels 8 m in the 1st second of travel, 8 m again during the 2nd second of travel, and 8 m again during the 3rd second. Its acceleration is
0 m/s
what is the acceleration of a car that maintains a constant velocity of 100 km/h for 10 s?
0 m/s/s
a 50 N object falling in air experiences 30 N of air resistance. the amount of net force on the falling object is
20 N
the average speed of a horse that gallops a distance of 10 km in a time of 30 min is
20 km/h
While in an airplane flying at 100 km/h you look down from the window and spot another airplane flying at the same speed in the opposite direction. Relative to you, the speed of the spotted plane is
200 km/h
a man weighing 800 N stands at rest on two bathroom scales so that one scale sows a reading of 500 N the reading on the other scale is
300 N
a man weighing 800 N stands at rest on two bathroom scales so that his weight is distributed evenly over both scales the reading on each scale is
400 N
One half second after starting from rest, a freely falling object will have a speed of about
5 m/s
nelie runs the length of a 100 yard football field in a time of 20 sec her average running speed is
5 yards/s
a girl pushes a cart to the left with a 100-N force. a boy pushes it to the right with a 50-N force.
50 N to the left
A free-falling object has a speed of 30 m/s at one instant. Exactly one second later its speed will be
50 m/s
When a 10 N object is suspended at rest by two vertical strands of rope. the tension in each rope is
5N
an object is pulled with two forces. 10 N northward and 15 N southward. the magnitude of the new force is
5N
When a 10-kg block is simultaneously pushed toward the east with 20 N and toward the west with 15 N, the combination of these forces on the block is
5N east
An object in free fall has a speed of 60 m/s. One second later its speed is
70 m/s
the scientist to first introduce the concept of inertia was
Galileo
Compared with a 1-kg block of solid iron, a 2-kg block of solid iron has twice as much
Mass, volume, inertia
when you stand at rest on a pair of bathroom scales the reading on the scales will always
add to equal your weight
You hang from a pair of gym rings and the upward support forces of the rings will always
add up to equal your weight
you're lying on the sand on a breezy day when a pesky fly wishes to join you the breeze is blowing at a steady 2 m/s in order for the fly to land on you it should hover over you while flying
against the breeze at 2 m/s
an object is mechanical equilibrium is an object
all of the above
if a non- rotating object has no acceleration the we can say for certain that it is
all of the above
which has zero acceleration?
all of the above
if burl carried paul piggy-back while standing in the middle of a scaffold, the tensions in the two supporting ropes would
be equal
while a crate rests on a horizontal floor the friction force acting on the crate is
between zero and the weight of the crate
Aristotle treated motion by
classifying it into two classes.
a tutor will be correct in saying that velocity and acceleration are
different concept
the two measurements necessary for calculating average sped are
distance and time
a parachutist falling at constant velocity is in a state of
dynamic equilibrium
a bucket of cement is raised by a rope at constant speed at a construction site. the upward force on the bucket supplied by the rope is
equal to the force of gravity
According to Galileo, the test of scientific truth is
experiment
In contrast to Aristotle's way of explaining nature, Galileo relied on
experiment
science greatly advanced when Galileo favored
experiment
A motor scooter undergoes acceleration when it
gains speed, decreases speed, and changes direction
the resistive force of friction occurs for
gases, liquids, solids
the amount of friction that occurs when two blocks slide against each other depends on
how much they are pressed together and the stickiness of atoms on their surfaces
when a crate slides down an incline at a constant velocity it is in a state of
in dynamic equilibrium
During each second of free fall, the speed of an object
increases by the same amount
An object that has twice as much mass as another object also has twice as much
inertia
a glance at your speedometer will tell you your
instantaneous speed
When a ball increases in speed by the same amount each second, its acceleration
is constant
the acceleration of a cart moving down an inclined plane
is constant
whenever the net force on an object is zero, its acceleration
is zero
when Galileo rolled a ball down an incline and up another incline, he found that the ball rolled nearly to
its initial height
Galileo said that if you rolled a ball along a level surface it would
keep rolling without slowing down if no friction acted upon it
Aristotle believed that natural laws could be understood by
logic
you would have the largest mass of gold if it weighed 1 N on th
moon
At the end of 2 seconds of free fall, an apple falling from rest has a speed of
more than 10 m/s
and object is pulled with three forces one at 20 N to the right, another at 40 N to the right, and the third at 30 N to the left. the net force is
none of the above
at the end of two seconds of free fall, an object released from rest will have a speed of
none of the above
compared with a 1-kg block of solid iron , a 2-kg block of solid iron has the same
none of the above
the equilibrium rule F= 0 applies to
objects or systems in uniform motion in a straight line and at rest
Acoording to Galileo, inertia is a
property of all matter
Galileo's demonstration at the leaning tower of pisa
refuted Aristotle's teachings
An object is pulled with two forces 10 N northward and 15 N southward. the magnitude of the new force is
south
when you push your desk to the right, friction on the desk acts toward
the left
An object weighs 30 N on Earth. A second object weighs 30 N on the moon. Which has the greater mass?
the moon
what did Galileo incorporate in his study of motion that Aristotle overlooked?
the role of time
compared with the mass of a certain object on earth, the mass of the same object o the moon is
the same
when you push a crate across the level floor at constant speed, friction between the crate and the floor is
the same amount as your pushing force
when she hikes a distance of 1 km in a time of one-half hour her average speed is
twice 1 km/hr
when you stand at rest on a floor, the number of vertical forces acting on you is
two
As an object freely falls, its
velocity increases
If you toss a ball straight upward at 40 m/s with no air resistance, 6 seconds later its speed is
zero
If you toss a ball straight upward at 40 m/s with no air resistance, one second before it reaches the top of its path its speed is
zero
if you toss a ball straight upward at 40 m/s with no air resistance, one second after it reaches the top of its path its speed is
zero
the speed of a vertically- thrown ball at the top of its path is
zero