Chapter 4: Newton's Second Law of Motion Flashcards
The mass of an object
Is not a vector and has no direction
Consider a car at rest, parked on level ground. The force of friction between a car tire and the ground
Is zero
In order to state the force exerted on one object by another object you must give
Both the magnitude of the force and the direction of the force
Under which circumstances is a force exerted on an apple by your hand?
When the apple is at rest in your open hand
This is a measurement of an object’s inertia
Mass
Which of the following is a valid force that could be exerted on a baseball?
The force on a baseball being hit by a bat
Which of the following is a legitimate way to describe the force between a skydiver and the earth as the skydiver is falling toward the ground?
The force of gravity exerted by the Earth on the skydiver
You are lying on your back on the slope of a grassy hill, watching the clouds go by overhead. Which of the best statement about the force of friction exerted on you by the ground in this situation?
A force of static friction pointing “up the hill” parallel to the surface of the hill, is applied to you by the ground
Acceleration can be expressed in units of m/s^2 or
N/kg
Which of the following statement is true about sliding friction?
Sliding friction is always in the direction that opposes motion
The acceleration of an object during free fall depends on the
Amount of gravity
In general, when a car is driving along a straight road, the force of friction between a car tire and the road
Can point either forward or backward, depending on what the car is doing
If you know all of the forces acting on an object and you know the mass of that object, what quantities can you figure out from that information?
The acceleration of the object
If you could somehow increase the mass of an object, what would happen to the net force on the object?
The net force on an object does not depend on the object’s mass
Newtons and pounds are
Different units fro measuring forces
Which of there is a valid force that could be exerted on a car racing through narrow city street?
The force of friction between the road and the car (its tires)
Newtons and kilograms
Unit for different quantities, and cannot be converted to each other
Under which circumstances, is there a force exerted on the apple by your hand?
When you are picking the apple up off the floor
An object’s mass and weight are
Proportional to each other
Forces can be expressed in units of
Newtons or pounds
Two identical car are traveling down the road. Car A is traveling at 60 mph, and car B is traveling at 40 mph. Which car has more friction acting on it?
Neither, both cars have the same amount of friction
When trying to analyze the forces in a situation we sometimes invent forces that don’t actually exist. Which of these force is Not a valid force that could be exerted on a sled being pulled along a snowy path by a girl?
The force of motion pushing the sled forward
You are about to check out at the grocery store, and you put a box of cereal on the converyer belt at the register. The cashier turns on the conveyors belt, causing the box of cereal to speed up momentarily. At this moment, what can we say about the frictional force acting on the box of cereal?
There is a static frictional force pointing in the box’s direction of motion, parallel to the conveyor belt
Which of the following is a legitimate way to describe the force between a skydiver and the air she is falling through as the skydiver
The drag force exerted by the air on the skydiver
Under which circumstances, is a force exerted on an apple by your hand?
When the apple is at rest in your open hand
