OVERALL REVIEWER Flashcards
Slamming on the brakes in a moving car makes a passenger move forward against his or her seat belt because…
the passenger has the inertia to keep moving forward
the passenger is being pushed by the seats of the car
the passenger is better able to stop themselves in this manner
the passenger has an equal and opposite force supporting their weight
the passenger has the inertia to keep moving forward
How long will an object remain at rest, according to Newton’s First Law of Motion?
it can’t rest
until noon
until an unbalanced force occurs
as long as there are unbalanced forces acting on it
until an unbalanced force occurs
For every _______ there is an equal and opposite ________.
reaction, action
action, action
reaction, reaction
action, reaction
action, reaction
Which of these is an example of Newton’s First Law, inertia?
pushing against a brick wall, and the brick wall does not move
pushing against a stationary wheelbarrow, and the wheelbarrow accelerates forward
pushing a wheelbarrow full of bricks, and the bricks slide back toward the handles
pushing a wagon to the top of a hill, and the wagon to the top of hill and the wagon accelerates down the hill without assistance
pushing a wheelbarrow full of bricks, and the bricks slide back toward the handles
You are sitting in a car that isn’t moving; the car accelerates. Your body is pushed back. Explain.
newtons
vector
inertia
gravity
inertia
Why is it harder to push a van filled with bowling balls than it is to push a van with basketballs?
The mass of the car is greater than the mass of the basketballs
The mass of the bowling balls is greater than the mass of the basketballs
The van with the basketballs is bigger than the van with the bowling balls
It should be equally as hard to push the two vans
The mass of the bowling balls is greater than the mass of the basketballs
You are holding a bowl of hot soup while standing in the kitchen. As you begin to move, the soup spills out of the bowl. Upon reflection you realize that…
the soup spilled because of air resistance
if you had traveled faster this wouldn’t have happened
the soup wanted to stay where it was, but you moved the bowl
the soup and the bowl act as one body with the same velocity
the soup wanted to stay where it was, but you moved the bowl
Why do you lean towards the left when a car turns right
because of inertia
because of gravity
because of buoyancy
because of velocity
because of inertia
You pull a wagon with your younger sister in it. Which of these would accelerate the rate at which you can pull the wagon?
pull the wagon with less force
Pull the wagon with more force
Have your sister push down on the wagon
Put another of your siblings in the wagon
Pull the wagon with more force
A wheelbarrow is experiencing two forces. One is pushing 5N east and another 5N west. What is true about the motion of the wheelbarrow?
it isn’t moving
it is accelerating
it is slowing down
its speed is constant
it isn’t moving
When a person jumps horizontally off the end of a boat, the person goes forward and the boat goes backward. This is an example of…
inertia
action and reaction
Newton’s 1st law
Newton’s 2nd law
action and reaction
A cup of coffee sits on the dashboard of an automobile. The car goes around a sharp curve. Even though you hold the cup still, coffee splashes out. This is explained due to…
density
friction
gravity
inertia
inertia
When a Civil War era cannon is fired, the force of the gas produced by exploding powder propels the cannonball forward at a high speed. According to Newton’s 3rd law…
the cannon itself moves backward
the cannon itself does not move due to inertia
the cannon itself moves forward as well with the momentum
the cannon itself moves forward with the inertia of the cannonball
the cannon itself moves backward
Pat measure a small rubber ball and makes 3 other balls of the same diameter from lead, foam, and wood. Which has the greatest inertia?
rubber ball
lead ball
foam ball
wood ball
lead ball
When you push a boat off from the dock, you are demonstrating Newton’s 3rd Law of Motion. It simply states that for every action there is an equal and opposite _______________?
Motion
Change
Reaction
Push
Reaction
According to Newton’s Third Law, what is the equal and opposite force to the downward force of gravity on a man standing on the beach?
the man pulling upward on the earth
the force of friction holding the man still
the pull of the sun keeping the earth in orbit
the surrounding air pressure keeping the man in equilibrium
the man pulling upward on the earth
Forces that are equal in size but opposite in direction are called ________________. _____________do not cause a change in motion. When _______________ act on an object at rest, the object will not move.
Balanced forces
The symbol for momentum in physics is the letter ___.
p
_______ is a change in momentum.
impulse
Applying a force for a longer time increases the change in _________. is the measure of a body’s translational motion - its tendency to continue moving in a particular direction.
Momentum
Which has a greater momentum: a semi-truck at rest or a bicycle in motion?
Bicycle
An objects momentum can be calculated by multiplying the velocity of the object by its_____.
Mass
_________ can be defined as “mass in motion.” All objects have mass; so if an object is moving, then it has _______.
Momentum
Momentum depends upon 2 variables:
Mass and Velocity
Momentum is a vector
True
Momentum is a vector, so the direction of momentum is the same as the direction of the velocity vector. An object’s momentum will change if its mass and/or velocity (speed and direction) changes
True
According to Newton’s laws, a net force causes an object to accelerate, or change its velocity. A net force, therefore, causes a change in an object’s momentum.
True
Momentum Question: Two trains, Big Red and Little Blue, have the same velocity. Big Red, however, has twice the mass of Little Blue. Compare their momentum.
Because Big Red has twice the mass of Little Blue, and Big Red must have twice the momentum of Little Blue.
If momentum changes, its because mass or velocity change. Most often mass doesn’t change so velocity changes and this is acceleration.
True
And then we get:
p = mass x Δv (Don’t forget Δ is “change in”)
p = mass x Acceleration
p = force
A change in momentum is known as an ____________.
impulse
The vector quantity for impulse is represented by the letter “J”, and since it’s a change in momentum, its units can be one the same as those for momentum, [kg·m/s], and can also be written as a Newton-second [N·s].
True
Applying a force over a time interval to an object changes the momentum.
True
What is the velocity of a 1.5 kg rock falling with a kinetic energy of 48 J?
8 m/s
A bulldozer pushed a large rock with a force of 5000 N at 2.0 m/s for 20 s. How much work was done on the rock by the bulldozer?
W = f x Δd
f = 5000N
Δd = v x t = 2.0m/s x 20s = 40m
W = 5000N x 40m = 200000 J or 2 x 10^5 J
A 2000kg car with a velocity of v collides head on with a 6000kg truck with a velocity of -v. Which vehicle experiences the greater force? Which experiences the greater acceleration?
(a) the truck experiences the greater force and the greater acceleration
(b) Both the car and the truck experience equal force and acceleration
(c) the car experiences the greater force and the greater acceleration
(d) The car and the truck experience equal force and the car experiences greater acceleration
(d) The car and the truck experience equal force and the car experiences greater acceleration
NASA’s Langley Research Center has been experimenting with the use of air bags to soften the landings of crew exploration vehicles (CEV) on land. What stopping time will be required in order to safely stop a 341 kg CEV moving at 7.85 m/s with an average force of 4300 N?
0.624 seconds
