Indietrophysics chapter 4 dynamic study module
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When trying to analyze the forces in a situation we sometimes invent forces that don’t actually exist. Which of these forces 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
Under which circumstance is there a force exerted on the apple by your hand?
When you are picking the apple up off of the floor.
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 is falling toward the ground?
The drag force exerted by the air on the skydiver
An object’s mass and weight are _____.
Proportional to each other
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 doesn’t depend on the object’s mass.
The mass of an object ______.
is not a vector and has no direction.
Newtons and kilograms are __________.
units for different quantities, and cannot be converted to each other.
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 is the correct choice.
This is a measurement of an object's inertia.
Mass
Which of these is a valid force that could be exerted on a car racing through narrow city streets?
The force of friction between the road and the car (its tires)
Newton's Second Law is correctly stated as __________.
A net force acting on an object causes it to accelerate
Acceleration can be expressed in units of m/s2 or __________.
N/kg
Under which circumstance is a force exerted on an apple by your hand?
When the apple is at rest in your open hand
The acceleration of an object during free fall depends on the __________.
amount of gravity
Forces can be expressed in units of __________.
newtons or pounds
Which of the following statements is true about sliding friction?
Sliding friction is always in the direction that opposes motion
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
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
Consider a car at rest, parked on level ground. The force of friction between a car tire and the ground _____________________.
is zero
You are lying on your back on the slope of a grassy hill, watching the clouds go by overhead. Which is 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.
Two identical cars 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.
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.
You are about to check out at the grocery store, and you put a box of cereal on the conveyer belt at the register. The cashier turns on the conveyor 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 conveyer belt
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
Newtons and pounds are __________.
different units for measuring force