physicis chapter 4

a car travels east at constant velocity the net force on the car is

zero

an action/ reaction pair of forces

act on two different objects

a force of 1N is

1kg*m/s^2

equal forces act on isolated bodies, A and B, the mass of B is 3x the mass of A, the magnitude of acceleration of A is

3x that of B

a woman is straining to lift a large crate, but without success because it is too heavy. how are the magnitudes of the forces related while the person tries unsuccessfully to lift the crate (P is upward force, C is vertical constant force, W is the weight)

P+C=W

newtons first law

an object in motion will continue in motion at a constant velocity unless acted on by a net external force

a steel beam hangs from a cable as a crane lifts the beam, what forces act on the beam

gravity and tension in the cable

the term mass refers to the same physical concept as

inertia

the mass of a body

is independent of the acceleration due to gravity

You stand on a spring scale on the floor of an elevator. Of the following, the scale shows the highest reading when the elevator:

moves upward with increasing speed or moves downward with decreasing speed

a circus performer of weight W is walking along a high wire, the tension in the wire is

much more that W

acceleration is always in the direction

of the net force

the inertia of a body tends to cause the body to

resist any change in its motion

newtons second law

the acceleration of an object is proportional to the net force on it and inversely proportional to its mass

magnitude of the acceleration of an object the least

the magnitude of forces in opposite direction

magnitude of the acceleration of an object the greatest

the magnitude of forces in the same direction

in general any surface exerts two forces on objects that are in constant with it, one force is parallel to the surface and the other is perpendicular to the surface, what are these forces called

the parallel force is friction force and the perpendicular force is the normal force

using a rope an object is lowered at a steady decreasing speed

the rope tension is greater than the objects weight

a feather and a lead ball are dropped from rest in vacuum on the moon, the acceleration of the feather is

the same as the lead ball

a 1500kg car travels a straight track at 60mph, a skier speeds up as she skies downhill, which is the net force greater

the skier

if you are standing on the floor motionless what are the forces that act on you

weight force and normal force

mass differs from weight in that:

weight is a force and mass is not

if you are not wearing a seat belt and the car you are driving hits a fixed barrier you will hit the steering wheel with some force, this is because

you continue moving even after the car has stopped