PS Test Ch 2

The net force on an object moving at a constant 30 m/s in a straight line is

-is 0 -is g -is its weight

The resistive force of friction occurs for (3 things)

-solids -liquids -gas

mass is

-the same everywhere -a measure of an object's inertia -amount of matter in an object

Lurching forward when the brakes are applied to a moving car is an example of (which law)

1st law

Which of Newton's Laws of Motion states in part, "An object at rest remains at rest" ?

1st law

Applying twice as much force to cause twice as much acceleration to an object is an example of Newton's ....

2nd law

Which of Newton's Laws of Motion states, "A net force produces an acceleration in the same direction as the net force proportional to the net force inversely proportional to the mass" ?

2nd law

A 100 kg car accelerates at 3 m/s2. What is the force produced by this acceleration?

300 N

"When one object exerts a force on another object, the second exerts an equal but opposite force on the first" describes Newton's _____Law.

3rd law

Understanding that when a bat hits a ball there is an equal force exerted by the ball on the bat is an example of Newton's

3rd law

(SLO2) A man weighing 800 N stands at rest on two bathroom scales so that his weight is distributed evenly over both scales. The reading on each scale is

400 N

If 10 N pull east and 15 N pull west, the net force is

5 N west

A skydiver who weighs 500 N reaches terminal velocity. The air resistance on the skydiver is

500 N

Newton's 1st law

Every object continues in a state of rest or of uniform speed in a straight line unless acted on by a nonzero net force

Newton's second law

The acceleration produced by a net force on an object is directly proportional to the net force, is in the same direction as the net force, and is inversely proportional to the mass of the object. -a=f/m

inertia

The tendency of an object to resist a change in motion (laziness)

free fall

When there is no longer air resistance and the only force is the gravitational pull between an object and the earth -accels at 10 m/s^2 -dependent on object's mass

newton's 3rd law

Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first. -to every action, there is an equal and opposite reaction (action and reaction are interchangeable)

Comparing a heavy parachutist and a light weight parachutist, the heavy parachutist falls with ________ terminal velocity.

a higher

When you stand at rest on a pair of bathroom scales, the readings on the scales will always ____________ no matter how you shift your weight between them.

add equal to your weight

Objects in free fall hit the ground ___ when dropped from the same height.

at the same time

The acceleration of an object falling with air resistance

decreases

When an object falls downward and has air resistance acting on it, the net force

decreases

A given net force propels an object along a straight-line path. If the net force were doubled, its acceleration would

double

An object at rest or an object in constant velocity motion remain that way because of what?

due to inertia

When a bug hits the windshield with 5 N of force, the windshield hits the bug back with _____ force.

exactly 5 N

The acceleration of an object in free fall is represented by

g

ratio of weight to mass is the constant _____

g -f/m=g

whenever the net force on an object is 0, its acceleration ___________

is zero

Newton's First Law is another way of describing

mechanical equilibrium

The reaction force to weight is

object pulling up on the earth

When an object falls downward in free fall, the net force

remains constant

When you push a crate across a level floor at constant velocity, friction between the crate and the floor is

same amount as your pushing force

force

simply, a push or pull. -also an interaction between 2 or more objects acting on each other

Air resistance, or drag, is primarily influenced by

speed and surface area

your weight is

the gravitational attraction between you and the earth

force pair

two objects equal in magnitude and opposite in direction (hand on wall)

terminal velocity

when terminal speed occurs in a certain direction (usually downwards)

terminal speed

when weight and air resistance are equal to each other, the object stops accelerating and remains at a constant speed