Section 1
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When you walk at an average speed of 4 m/s, in 5 s you'll cover a distance of
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Date created
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Cards (200)
Section 1
(50 cards)
When you walk at an average speed of 4 m/s, in 5 s you'll cover a distance of
20 m
The time it takes a projectile fired straight up at 10 m/s to reach the top of its path is about
1 s
A force is a vector quantity because it has both
magnitude and direction
If a freely falling object were equipped with a speedometer, its speed reading would increase each second by about
10 m/s
A gymnast performing somersaults in a high-flying plane moving at constant velocity needs to make
no adjustments.
If an object falling freely were somehow equipped with an odometer to measure the distance it travels, then the amount of distance it travels each succeeding second would be
greater than the second before
A rock dropped from a 5-m height accelerates at 10 m/s2 and strikes the ground 1 s later. If the rock is dropped from a height of 2.5 m, its acceleration of fall is
the same
The two measurements necessary for calculating average speed are
distance and time
Neglecting air resistance, a bullet fired straight down from the top of a high cliff has an acceleration of
10 m/s^2
A bullet is dropped into a river from a very high bridge at the same time as another bullet is fired straight downward from a rifle. Neglecting air resistance, the acceleration just before striking the water is
same for each bullet
An object at rest near the surface of a distant planet starts to fall freely. If the acceleration there is twice that of the Earth, its speed one second later would be
20 m/s
If a freely falling object were equipped with a speedometer on a planet where the acceleration due to gravity is 20 m/s2, then its speed reading would increase each second by
20 m/s
A vehicle undergoes acceleration when it
- loses speed - changes it direction - Gains speed
Ten seconds after starting from rest, a car is moving at 40 m/s. What is the car's acceleration?
4.0 m/s^2
If an object moves with constant acceleration, its velocity must
change by the same amount each second
A mosquito flying at 3 m/s that encounters a breeze blowing at 3 m/s in the same direction has a speed of
6 m/s
An 80-km/h airplane flying against a 10-km/h head wind has a groundspeed of
70 km/h
If a rocket initially at rest accelerates at a rate of 50 m/s2 for one minute, its speed will be
3000 m/s
Neglecting air resistance, how fast must you toss a ball straight up in order for it to take 6 seconds to return to its initial level?
30 m/s
A ball starting from rest at the top of an inclined plane accelerates at 2 m/s2 and reaches the bottom of the plane in 3 seconds. What is the length of the plane?
9 m
An object covers a distance of 8 meters in the first second of travel, another 8 meters during the next second, and 8 meters again during the third second. Its acceleration is
0 m/s2
At one instant an object in free fall is moving downward at 50 m/s. One second later its speed is
60 m/s
Jogging Jake runs at 4 m/s along a train flatcar that moves at 10 m/s in the same direction. Jake's speed relative to the ground is
14 m/s
An 80-km/h airplane flying in the same direction as a 10 km/h tail wind has a groundspeed of
90 km/h
One half second after starting from rest, a freely falling object will have a speed of about
5 m/s
A cart maintains a constant velocity of 100 m/s for 10 seconds. During this interval its acceleration is
zero
While a car travels around a circular track at a constant speed, its
none of the above
A ball starting from rest at the top of an inclined plane gains a speed of 2 m/s for each second it rolls. What is its acceleration down the incline?
2 m/s^2
A freely-falling watermelon falls with constant
acceleration
You're at rest in a hammock when a hungry mosquito sees an opportunity for lunch. A mild 2-m/s breeze is blowing. If the mosquito joins you for lunch it should hover over you by flying
against the breeze at 2 m/s
A block pulled to the left with 15 N and to the right with 5 N at the same time experiences a net force of
10 N
Katelyn runs along the aisle of a train that moves at 8 m/s. Her speed relative to the floor is 3 m/s. Her speed relative to an observer at rest on the ground is
depending on her running direction
When a ball thrown straight upwards reaches the very top of its path, its acceleration is
10 m/s^2
A mosquito flying at 3 m/s that encounters a breeze blowing at 3 m/s in the opposite direction has a speed of
0 m/s
A car's speed 3 seconds after accelerating from rest at 2 m/s2 is
6 m/s.
Which of the following is not a vector quantity?
speed
While an iron block near the Earth's surface is in free fall, it undergoes an increase in
speed
A ball tossed vertically upward rises, reaches its highest point, and then falls back to its starting point. During this time the acceleration of the ball is always
directed downward.
The total time it takes a projectile fired straight up at 10 m/s to reach the top of its path and return to its starting point is about
2 s
If you throw a ball straight downward (in the absence of air resistance), after leaving your hand its acceleration is
10 m/s^2
At one instant a heavy object in air is moving upward at 50 m/s. One second later its speed is approximately
40 m/s
If a stone falls to the bottom of a mineshaft in 6 seconds, then the depth of the shaft is about
180 m
The speedometer of an automobile reads
instantaneous speed
A cart changes its speed from 90 m/s to 100 m/s in 10 seconds. During this interval its acceleration is
1m/s^2
Jogging Jake runs at 4 m/s along a train flatcar that moves at 10 m/s in the opposite direction. Jake's speed relative to the ground is
6 m/s
What is the acceleration of a car that starts from rest and 5 seconds later reaches a speed of 20 m/s?
4 m/s^2
The distance a freely falling bowling ball falls each second
increases
The average speed of a horse that gallops 10 kilometers in 30 minutes is
20 km/h
If a car increases its velocity from zero to 60 m/s in 10 seconds, its acceleration is
6 m/s^2
An object falls freely from rest on a planet where the acceleration due to gravity is 20 m/s2. After 5 seconds, the object will have a speed of
100 m/s
Section 2
(50 cards)
When you flick a card from beneath a coin that hardly moves, you're illustrating
inertia
A 1-kg rock that weighs 10 N is thrown straight upward at 20 m/s. Neglecting air resistance, the net force that acts on it when it is half way to the top of its path is
10 N
When you stand at rest on a pair of bathroom scales, the reading on each scale
add up to equal your weight.
If no external forces act on a moving object, it will
continue moving at the same speed.
Weigh yourself on a weighing scale and the scale shows your normal weight. If you carefully stand on tiptoes, the scale reading will be
no different
Jason weighs 150 N and sits on his big brother's shoulders. Big brother weighs 400 N. The support force supplied by the floor must be
550 N
A boulder following a straight-line path at constant velocity has
zero acceleration
A sheet of paper can be quickly jerked beneath a container of milk without toppling, which best demonstrates
inertia
When you quickly jerk a cart forward that has a ball resting in the middle, the
back of the cart hits the ball.
A hockey puck sliding across the ice finally comes to rest because
of friction
The amount of force needed to sustain motion of a rock in outer space is
- force equal to its weight. - a force less than its weight if friction is absent. - none of these !!!!!
A 10-kg brick and a 1-kg apple are dropped in a vacuum. The force of gravity on the brick is
10 times more than the force on the apple.
If your automobile runs out of fuel while driving, the engine stops. You don't come to an abrupt stop due to
inertia
A 10-N block and a 1-N block lie on a horizontal frictionless table. To impart equal horizontal accelerations, we would have to push the heavier block with
10 times as much force.
A hockey puck is set in motion across a frozen pond. If ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is
none of the above
The equilibrium rule, ΣF = 0, applies to
objects or systems at rest. objects or systems in uniform motion in a straight line
If you toss a coin straight upward while in a train moving at constant velocity, the coin will land
as if you were at rest
An 800-N man 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
A hockey puck sliding at constant velocity across the ice is
equilibrium
A 500-N parachutist opens his chute and experiences an air resistance force of 800 N. The net force on the parachutist is then
300 N upward
Nellie pulls with a force of 50 N on a horizontal rope tied to a tree at rest. The net force on the rope is
zero and rope tension is 50 N.
Inertia is defined as a
property of matter
The equilibrium rule applies to
vector quantities.
If you toss a coin straight upward in train that gains speed while the coin is in the air, the coin will land
in back of you
When no forces act on moving objects their paths are normally
straight lines
A car by itself is capable of a certain maximum acceleration. When it tows a car of the same mass, its maximum acceleration is
one half
A tree stump is pulled northward by a 10-N force at the same time a 25-N force pulls it southward. The resultant force has a magnitude of
15N
A 1-kg ball is thrown at 10 m/s straight upward. Neglecting air resistance, the net force that acts on the stone when it is halfway to the top of its path is about
10 N
The support force on a 30-kg dog sleeping on the floor is
about 300 N
The support force on a 10-N book at rest on a table is
10 N
Two students engaged in a tug-of-war each pull a rope in opposite directions with a force of 400 N. The net force on the rope is
zero and rope tension is 400 N.
A 300-kg bear grasping a vertical tree slides down at constant velocity. The friction force between the tree and the bear is
3000 N
The force of friction on a sliding object is 10 N. The applied force needed to maintain a constant velocity is
10 N
Which concept is being illustrated when a tablecloth is quickly yanked beneath dishes resting on a table?
inertia
If you toss a coin straight upward in train that slows while the coin is in the air, the coin will land
in front of you
A 2000-kg car experiences a braking force of 10,000 N and skids to a stop in 6 seconds. The speed of the car just before the brakes were applied was
30 m/s
Which of the following is a vector quantity?
none
A bag of groceries that has a mass of 10 kilograms weighs about
100 N
The net force acting on an insect falling downward at constant velocity is
zero
The net force on any object in equilibrium is
zero
Suspend your body from a pair of vertical ropes and the tension in each rope will be
half your weight
When a rocket ship gaining speed in outer space runs out of fuel, it
no longer gains speed
Due to inertia, perhaps a railroad train in motion should continue moving indefinitely when its engine is turned off. This is not observed because railroad trains
encounter opposing forces
A block is dragged without acceleration in a straight-line path across a level surface by a force of 6 N. What is the force of friction between the block and the surface?
6 N
A 1-kg mass at the Earth's surface weighs
10 N
While you are standing in the aisle of a bus, the driver suddenly makes a left turn. You lurch to the right due to
tendency to keep moving foward
A 10-kilogram block is pushed across a horizontal surface with a horizontal force of 20 N against a friction force of 10 N. The acceleration of the block is
1 m/s^2
An object in mechanical equilibrium is an object
all og the above
A 10-N falling object encounters 10 N of air resistance. The net force on the object is
0 N
Earth continually moves about 30 km/s through space, which means the wall you stand next to also is moving at 30 km/s. When you jump vertically the wall doesn't slam into you because
you're moving horizontally just as fast as the wall.
Section 3
(50 cards)
Phil stands at rest with both feet on a scale that reads 500 N. When he gently lifts one foot, the scale reads
500 N
A sack of potatoes weighing 200 N falls from an airplane. As the velocity of fall increases, air resistance also increases. When air resistance equals 200 N, the sack's acceleration becomes
0 m/s^2
Suppose a particle is being accelerated through space by a 10-N force. Suddenly the particle encounters a second force of 10 N in the opposite direction. The particle with both forces acting
continues at the speed it had when it encountered the second force.
A push on a 1-kg brick accelerates it. Neglecting friction, equally accelerating a 10-kg brick requires
10 times as much force
Strange as it may seem, it is just as difficult to accelerate a car on a level surface on the Moon as it is here on Earth because
the mass of the car is independent of gravity.
Recall Galileo's Leaning Tower experiment. With negligible air resistance, a heavy and a light object fall
with equal accelerations. to the ground in equal times. with the same increases in speed.
A rock is thrown vertically into the air. At the top of its path the net force on it is
mg
Your weight as measured on your bathroom scale is
the force due to gravity on you.
Suzie Skydiver, who weighs 500 N, reaches terminal velocity of 90 km/h. The air resistance on Suzie is then
500 N
Nellie pulls on a 10-kg wagon with a constant horizontal force of 30 N. If there are no other horizontal forces, what is the wagon's acceleration?
3.0 m/s^2
An apple weighs 1 N. When the apple is held at rest above your head, the net force on the apple is
0 N
The mass of a pet turtle that weighs 10 N is about
1 kg
If an object's mass is decreasing while a constant force is applied to the object, the acceleration
increases
Compared to the mass of an apple on Earth, the mass of the apple on the Moon is
the same
An object with twice as much mass as another object has twice as much
inertia
A rock is thrown vertically into the air. At the top of its path, its acceleration is
10 m/s^2
At equilibrium on a bathroom weighting scale, the downward pull of gravity on you is balanced by
an upwars support force
Which has zero acceleration? An object
in mechanical equilibrium. moving at constant velocity. at rest
A car traveling at 100 km/h strikes an unfortunate bug and splatters it. The force of impact is
the same for both.
If an apple experiences a constant net force, it will have a constant
acceleration
When you stand at rest with your left foot on one bathroom scale and your right foot on a similar scale, each of the scales will
show readings that when added equal your weight.
If you double the net force on an object, you'll double its
acceleration
Scotty Skydiver of mass 100 kg experiences air resistance of 500 N, and an acceleration of about
0.5 g
A tow truck exerts a force of 3000 N on a car, which then accelerates at 2 m/s2. What is the mass of the car?
1500 KG
The mass of a lamb that weights 110 N is about
11 kg
An apple at rest weighs 1 N. The net force on the apple when it is in free fall is
1 N
If the net force on a cart is tripled, the cart's acceleration
is three times as much
A jumbo jet has a mass of 100,000 kg. The thrust for each of its four engines is 50,000 N. What is the jet's acceleration when taking off?
2 m/s^2
Compared to a 1-kg block of solid iron, a 2-kg block of solid iron has twice as much
- mass - inertia - volume
You drive your car at a constant 60 km/h along the highway. You apply the brakes until the car slows to 40 km/h. If at that moment you suddenly release the brakes, the car tends to
continue moving at 40 km/h.
A rock weighs 30 N on Earth and another rock weighs 30 N on the Moon. Which rock has the greater mass?
the one on the moon
If the mass of a cart is quickly loaded to have twice the mass while a propelling force remains constant, the cart's acceleration
halves
A player hits a ball with a bat. If action is the force of the bat against the ball, reaction is the
force that the ball exerts on the bat
Whenever the net force on an object is zero, its acceleration
is zero
An object's weight is properly expressed in units of
newtons
A car has a mass of 1000 kg and accelerates at 2 m/s2. What net force is exerted on the car?
2000 N
The brakes of a speeding truck are slammed on and it skids to a stop. If the truck were heavily loaded so that it had twice the total mass, the skidding distance would be
the same
The human body can withstand an acceleration of 10 g under certain conditions. What net force would produce this acceleration for a 50-kg person?
5000 N
A constant net force on a rail-road car produces constant
acceleration
A mobile phone is pulled northward by a force of 10 N and at the same time pulled southward by another force of 15 N. The resultant force on the phone is
5 N
In which case would you have the largest mass of gold? If your chunk of gold weighed 1 N on the
moon
When a falling object has reached its terminal velocity, its acceleration is
zero
The force required to maintain a constant velocity for an astronaut in free space is equal to
zero
The newton is a unit of
force
A car traveling at 22 m/s comes to an abrupt halt in 0.1 second when it hits a tree. What is the deceleration of the car?
220 m/s^2
A player catches a ball. If action is the force of the ball against the player's glove, reaction is the
glove against the ball
A car by itself is capable of a certain maximum acceleration. When it tows a twice-as-massive car, its maximum acceleration is
one third
A force of 1 N accelerates 1-kg box at the rate of 1 m/s2. The acceleration of a 2-kg box by a net force of 2 N is
the same
A heavy block at rest is suspended by a vertical rope. When the block accelerates upward by the rope, the rope tension
is greater than its weight.
A kilogram is a measure of an object's
mass
Section 4
(50 cards)