chapter 12 pretest and quizzes
Express the following as an equation: One newton is the force that can give an object with a mass of 1 kg an acceleration of 1 m/s2.
1 N = 1 kg • 1 m/s2
One newton is the force that can give a mass of 1 kg an acceleration of _____________
1 m/s^2
What unbalanced force is needed to give a 854,000 g vehicle an acceleration of 1.25 m/s2?
1.068 x 10^3 N
What unbalanced force is needed to give a 976 kg vehicle an acceleration of 2.50 m/s2?
2.44 x 10^3 N
In drag racing, acceleration is more important than speed, and therefore drag races are designed to provide high acceleration. Suppose a drag racer has a mass of 1,250,000 g and accelerates at a constant rate of 16.5 m/s2. How large is the unbalanced force acting on the racer?
20,625 N
What is the momentum of a 255 g apple falling at 16.0 m/s? (hint: convert g to kg)
4.08 kg x m/s downward
Calculate the velocity of a 90.5 kg man running south with a momentum of 389 kg • m/s.
4.30 m/s south
A 0.25 kg steel ball experiences a net force of 1.15 N as it rolls down a ramp. What is the acceleration of the ball?
4.6 m/s^2
Calculate the velocity of a 70,500 g man running south with a momentum of 362 kg • m/s.
5.13 m/s south
Which of the following will result in the greatest acceleration?
56N acting on a 1kg box
How much does a 59.0 kg woman weigh on Earth? What is her "scientific" weight?
578 N
A force of 240.0 N causes an object to accelerate at 3.2 m/s^2. What is the mass of the object?
75kg
What is the known value of acceleration of objects in free fall near earth's surface?
9.8 m/s2
Which statement illustrates Newton's first law?
A stone will not move unless something pushes or pulls it, A ball rolling across the floor eventually slows down, As a car comes to a stop, the passengers continue to move forward
What happens immediately after a skydiver opens her parachute?
Air resistance greatly increases.
Which of the following is true?
All of these are true statements.
The tendency of an object to resist a change in motion unless an outside force acts on the object.
Inertia
If two objects with different masses and traveling with different velocities collide, what law allows you to predict the motion of the objects after the collision?
Law of Conservation of Momentum.
The law that states that every object maintains constant velocity unless acted on by an unbalanced force is _______________________________
Newton's first law of motion.
The law that states that the unbalanced force acting on an object equals the object's mass times its acceleration is ___________________________________
Newton's second law of motion.
Earth pulls on the moon and holds the moon in its orbit. The moon pulls on Earth with an equal and opposite force. This is an example of?
Newton's third law
The law that states that for every action force there is an equal and opposite reaction force is ____________________________
Newton's third law of motion.
The curved path that an object follows when thrown, launched, or otherwise projected near the surface of Earth; the motion of objects that are moving in two dimensions under the influence of gravity is _______.
Projectile Motion
A small sports car traveling south collides with a heavy truck traveling north. Both vehicles are going at the same rate of speed. Which will be moved off course by the collision and in which direction?
The small sports car, north.
Which statement about action-reaction forces is incorrect?
They always act on the same object.
In the absence of air resistance, how would the acceleration of a 1.5 kg book and the acceleration of a 15 kg rock differ if the objects were dropped from the same height.
They would not differ; they would be the same, free fall; 9.8 m/s2
A measure of the gravitational force exerted on an object; its value can change with the location of the object in the universe. (Measured in Newtons: N)
Weight
Which object has the greatest inertia?
a bowling ball
Which of the following objects exerts a gravitational force?
a bowling, ball, a book, a feather (all of the above)
Which is an example of projectile motion?
a dart thrown at a dart board
Which of the following has a momentum of zero?
a newspaper lying on a table
Which object does not have momentum?
a rock by the side of the road (not moving)
Which of the following is not a factor in calculating momentum?
acceleration
Which statement about weight is incorrect?
an object weighs more on the moon than it does on Earth
Two identical cars are traveling at equal speeds. One is going no th and the other south. If they collide head-on and stick together, what will happen to the motion of the cars?
both cars will stop
The gravitational force between two objects depends on masses of objects and?
distance between objects
Whenever a force is exerted, another force occurs that is ________ in size, and ________ in direction.
equal; opposite
Orbital motion is a combination of _________________________________
forward motion and free fall
What force causes a skater sliding on the ice to gradually slow down?
friction
When an object is in free fall, the only force acting on it is?
gravity
Astronauts "float" when inside an orbiting spaceship because they are _________________
in free fall
Free-fall acceleration near Earth's surface _______________________________
is the same for all objects
When a moving bowling ball hits a pin, some of the ball's momentum ___________________________
is transferred to the pin
How does the total momentum of two objects before a collision compare with the total momentum after the collision?
it is the same
Increasing which of these conditions results in more gravitational force between two objects?
mass
An object's momentum is determined by the object's _____________________________
mass and velocity
The force exerted on the racket by a hit tennis ball is the _____________________
reaction force
When gravitational forces and air resistance equalize on an object that is falling toward Earth and the object stops accelerating, what is the velocity of an object called?
terminal velocity
Weight is best described as?
the downward force exerted on objects due to gravity
What is the unbalanced force that slows down a ball rolling across the floor?
the force of friction
What is the reaction force when you place a cup on a table?
the force of the table on the cup
Of the following, the greatest gravitational force would occur between?
the moon and Earth.
If an equal force is applied to two cars of equal mass, Car A and Car B, Car A will have ____________________ acceleration as (than) Car B.
the same
Which statement about action-reaction force pairs is incorrect?
they act on the same object
A seat belt helps you when your car stops suddenly by providing a(n)?
unbalanced backward force