Physical Science - Chapter 11
An ancient Greek philosopher who made many scientific discoveries through observation and logical reasoning
Aristotle
T/F Because the weight formula shows that mass and weight are proportional, doubling the mass of an object will not affect its weight.
False Doubling the mass of an object will double the weight. (ex. - 5 x 2 = 10; if double the mass (5), weight would be doubled at 20...10 x 2 = 20.)
T/F The law of intertia states that an object in motion will eventually slow down and come to a complete stop if it travels far enough in the same direction.
False Law of intertia states that an object at rest will remain at rest unless an unbalanced force acts AND An object in motion will remain in motion with the same speed and direction unless an unbalanced force acts
T/F If the same force acts upon two objects with different masses, the acceleration will be greater for the objects with greater mass.
False The formula for acceleration is Net Force/Mass. If the net force stayed the same (for example, 5) and the Mass of one object was 1 and the other object 2. Acceleration would be greater with the object with a lower mass (5/1 = 5; 5/2=2.5)
Italian scientist who did experiments that helped correct misconceptions about force and motion.
Galileo
What's the difference between Mass & Weight
Mass = measure of the amount of material an object contains Weight = measure of force of gravity acting on an object. (weight = mass x acceleration due to gravity)
Causes an object's velocity to change
Net Force
What's the formula for acceleration?
Net Force/Mass
Scientist who studied in England and introduced several laws describing force and motion
Newton
A person's weight on Mars, measured in _____________, is 0.38 times the weight on Earth.
Newtons
T/F According to Newton's first law of motion, an object's state of motion does not change as long as the net force acting on it is zero.
True
T/F The acceleration of an object is always in the same direction as the net force action on the object.
True
Formula for calculating weight of an object
Weight = Mass x Acceleration due to gravity
If an object is at rest, which of the following statements must be true? a. There are no forces acting on the object. b. There is no friction acting on the object. c. The forces acting on the object are unbalanced. d. The net force acting on the object is zero.
a. The net force acting on the object is zero
A ball thrown into the air follows a projectile course due to the initial velocity and the a. force of gravity. b. effect of air resistance. c. motion of Earth beneath it. d. mass of the ball.
a. force of gravity
When an unbalanced force acts on an object, the object does what?
accelerates
A change in an object's speed or direction of motion is called ________________.
acceleration
A 3600-N force causes a car to accelerate at a rate of 4 m/s2. What is the mass of the car? a. 600 kg b. 900 kg c. 14,400 kg d. 1200 kg
b. 900 kg weight = mass x accleration due to gravity 3600 = mass x 4 3600/4 = mass 900 = mass
The SI unit for force is 1 kg•m/s2, also called one kepler. a. True b. False
b. False The SI unit for force is 1 kg•m/s2, also called one NEWTON
In which direction does Earth's gravitational force act? a. opposite the direction of motion b. downward toward the center of Earth c. upward away from the center of Earth d. in the direction of motion
b. downward toward the center of the Earth
a center-directed _______________ continuously changes the direction of an object to make it move in a circle.
centripetal force
What type of friction does a sky diver experience which opposes the force of gravity? a. static b. sliding c. rolling d. fluid
d. fluid friction
Which of the following is not a type of friction? a. static friction b. sliding friction c. fluid friction d. pull friction
d. pull friction
What is inertia? a. the force of gravity acting on an object b. forces of friction slowing an objects motion c. the mass of an object d. the tendency of an object to resist change in its motion
d. the tendency of an object to resist change in its motion
How would your mass and weight change if you were on the moon's surface? a. They wouldn't change. b. Your mass would remain constant, and your weight would increase. c. Your mass and weight would decrease. d. Your mass would remain constant, and your weight would decrease.
d. your mass would remain constant, and your weight would decrease. ** because the gravity that you would multiply the mass by is less on the moon...making your weight less as well.
A force associated with charged particles is ___________________.
electromagnetic force
Push or pull that acts on an object
force
A force that opposes the motion of objects that touch as they move past each other is called _______________.
friction
The universal force that causes every object to attract every other object is _______________.
gravity
the tendancy of an object to resist a change in motion
inertia
On the moon, the acceleration due to gravity is only about 1/6th that on Earth. Thus, an object will weigh ___________ on the moon that it weighs on earth.
less Weight - Mass x acceleration due to gravity If Mass of an object is 10 and acceleration due to gravity on earth is 10, acceleration due to gravity on the moon would be 1.666 since it's 1/6th of that on earth. weight on earth = 10 x 10 = 100 weight on moon = 10 x 1.666 = 16.66
A measure of an object's intertia is it's ___________________
mass
According to Newton's second law of motion, acceleration of an object depends upon the __________ of the object and the _________ acting on it.
mass; net force
The product of an object's mass and it's velocity is _________________.
momentum
Four main types of friction
static friction, sliding friction, rolling friction fluid friction.
The Net Force is zero when what?
the forces on an object are balanced
The _______________force affects all particles in a nucleus and acts only over a short range.
weak nuclear
A measure of the force of gravity acting on an object is its ____________.
weight