chapter 4

An object moves in a circular path at a constant speed. What is the direction of the net force acting on the object?

toward the center of the circular path.

with correct relative force magnitudes, of a person in an elevator that is traveling upward but is gradually slowing down at a rate of 9 m/s2? F⃗ f is the force of the floor on the person and F⃗ g is the force of gravity on the person.

Fg is twice as much and Ff .

A box of mass m is pulled with a CONSTANT ACCELERATION a along a horizontal frictionless floor by a wire that makes an angle of 15° above the horizontal. If T is the tension in this wire, then

T > ma.

The same net force is applied to two different objects. Object 2 has twice the mass object 1

The acceleration of object 1 is twice the acceleration of object 2.

An object is hanging by a string from the ceiling of an elevator. The elevator is moving upward with a constant speed. What is the magnitude of the tension in the string?

The magnitude of the tension in the string is equal to the magnitude of the weight of the object.

An object is hanging by a string from the ceiling of an elevator. The elevator is slowing down while moving upward. What is the magnitude of the tension in the string?

The magnitude of the tension in the string is less than the magnitude of the weight of the object.

An object is moving with constant velocity. Which of the following best describes the force(s) acting on the object?

The net force acting on the object is zero.

Consider what happens when you jump up in the air. Which of the following is the most accurate statement

When you push down on the earth with a force greater than your weight, the earth will push back with the same magnitude force and thus propel you into the air.

circular path - net forces point to the

center of the path

when the net force is zero, the velocity is

constant

A constant net force acts on an object. Which of the following best describes the object's motion?

constant acceleration

An object is moving in the absence of a net force. Which of the following best describes the object's motion?

constant velocity.

when a body is at rest or moving with a constant velocity it is said to be in

equilibrium

An object is moving to the right, and experiencing a net force that is directed to the right. The magnitude of the force is decreasing with time. The speed is..

increasing

newtons first law

net force on a body must be zero if the body is in equilibrium

newton's second law

the acceleration on a body is proportional to the force acting on it and inversely proportional to the mass of the object

A 20-ton truck collides with a 1500-lb car and causes a lot of damage to the car. During the collision

the force of on the truck due to the collision is exactly equal to the force on the car

stalled car is being pushed up a hill at CONSTANT VELOCITY by three people. The net force on the car is

zero

when the net force is zero the acceleration is

zero