Galileo
Was it Galileo or Newton who first proposed the concept of inertia?
Law of motion, resistance, inertia
Consider a ball at rest in the middle of a toy wagon. When the wagon is pulled forward, the ball rolls against the back of a wagon. Interpret this observation in terms of Newton’s first law.
No, because an object will continue movement unless external forces acts upon it
When you push a cart, it moves. When you stop pushing it comes to rest. Does this violate Newton’s law of inertia? Defend your answer.
When at equilibrium the net force will be zero
When any object is in mechanical equilibrium, what can be correctly said about all the forces that act on it? Must the net force necessarily be zero?
No
Can you say that no force acts on a body at rest? Or is it correct to say that no net force acts on it? Defend your answer.
Yes. Force of friction (kinetic, because the object is moving)
On a long alley, a bowling ball slows down as it rolls. Is any horizontal force acting on the ball? How do you know?
Same
Since an object weighs less on the surface of the moon than on Earths surface, does it have less inertia on the moons surface?
16.3 N
Gravity on the surface of the moon is only 1/6 as strong as gravity on Earth. What is the weight of a 10kg object on the moon and on the Earth? What is the mass on each?
Mass
Does a dieting person more accurately lose mass or lose weight?
No
Free fall is motion in which gravity is the only force acting.
a) is a skydiver who has reached terminal speed in free fall?
b)is a satellite above the atmosphere that circles Earth in free fall?
a) is a skydiver who has reached terminal speed in free fall?
b)is a satellite above the atmosphere that circles Earth in free fall?
Acceleration due to gravity
When a coin is tossed upward, what happens to its velocity while ascending? It’s acceleration? (Neglect air resistance)
Two forces- weight of car and normal forces
A friend says that, as long as a car is at rest, no forces act on it. What do you say if you’re in the mood to correct the statement of your friend.
Action force- bat hits ball, reaction-ball hits bat
Consider a baseball player batting a ball.
a)identify the action-reaction pairs when the ball is being hit and b) while the ball is in flight
a)identify the action-reaction pairs when the ball is being hit and b) while the ball is in flight
Action- foot to ball, reaction- ball to foot
When you kick a football, what action and reaction forces are involved? Which force, if any, is greater?
Age- scalar
Speed- scalar
Acceleration- scalar
Temperature- scalar
Velocity- vector
Speed- scalar
Acceleration- scalar
Temperature- scalar
Velocity- vector
Which of the following are scalar quantities, which are vector quantities, and which are neither? Age, velocity, speed, acceleration, temperature
0, because there is no change in speed (velocity)
****Light travels on a straight line at a constant speed of 300,000 km/s. What is the acceleration of light?*****
Yes, its deceleration- opposite direction
Can an automobile with a velocity toward the north simultaneously have an acceleration toward the south? Explain.
No, because they didn’t give us time
Starting from rest, one car accelerates to a speed of 50 km/hr, and another car accelerates to a speed of 60 km/hr. Can you say which car underwent the greatest acceleration? Why or why not?
Yes, yes at the highest point
a) Can an object be moving when its acceleration is zero? If so, give an example.
b) Can an object be accelerating when it’s speed is zero? if so, give an example.
b) Can an object be accelerating when it’s speed is zero? if so, give an example.
Zero, because steady means constant
What is the acceleration of a car that moves at a steady velocity of 100 km/hr for 100 s? Explain your answer
25-30
Which is greater, an acceleration from 25 km/h to 30 km/h or one from 96 km/h to 100 km/h if both occur at the same time?
No, because acceleration is constant
As speed increases for an object in free fall, does acceleration increase also?
True
T/F: Newton’s first law deal with constant velocity (speed)?
Newton and pound
Which is a unity for weight?
False
T/F: The mass of an object is the same as the weight of the object?
150 N
If an weighs 150 N, what must the air resistance for be if the object is falling and has reached terminal velocity?
Arisotle
According to _____, an object always required a force to keep it in motion
120 km/h
What is the average speed of a horse that gallops a round trip distance of 30 km in a time of 15 minutes?
What is the average velocity for the round trip of the horse in the previous question?
96 ft/s
You drop a stone (from rest) downward. What is its speed 3 seconds later?
44.1
An object dropped from rest in free fall will fall ____ meter in 3 seconds
A book sliding to a stop on top of a table
Which of the following represents a situation when the acceleration of an object is not in the same direction as the net force acting on the object?
5 m/s^2
What is the magnitude of the acceleration of a 2 kg object when the net force of the object is 10 N?
True
T/F: Aristotle believed that when two objects when two objects with different masses ( one heavier than the other) drop from the top of a building, the heavier object will hit the ground first
The force applied to the bat to ball
Consider hitting a baseball with a bat. If we call the force applied to the ball by the bat the action force, identify the reaction force
False
T/F: True weight and apparent weight are always the same
122.5 meters
It takes 5 seconds for a stone to hit the water in a deep well. How far is it to the water?
Acceleration
Objects free fall near the Earth’s surface when there is no air resistance at constant ____
Force
Which of following causes the motion of an object
Speed and mass
Which of the following is a scalar quantity
Acceleration
A net force, acting on an object produces a(n)
Mass
A measurement of an inertia is called _____
