Phys Chapter 1 & 2 HW

Daisy weighs 120 N and carries trixie who weighs 40 N on her back. The support force on Daisy's feet is

160 N

Jake pulls on a 25 kg cart with a constant force of 50 N. what is the wagon's acceleration?

2.0 m/s squared

A 50-N object falling in air experiences 30 N of air resistance. The net force on a falling object is

20 N

The average speed of a horse that gallops a distance of 10 km in a time of 30 minutes is

20 km/h

When a ball increases in speeed by the same amount each second, its acceleration

is constant

According to Aristotle, a rolled ball eventually comes to a stop because

it seeks its natural state of rest.

A probe in space continues in its motion due to...

its own inertia.

Galileo said that if you rolled a ball along a level surface it would

keep rolling without slowing down if no friction acted upon it.

Aristotle believed that natural laws could be understood by

logic.

A kilogram is a unit of...

mass.

At the end of 1/2 second, an apple freely falling from rest has a speed of

more than 10m/s

A stone is thrown verticaly upward. At the top of its vertical path, the force acting on it is

only the force due to gravity

A hockey puck slides across a frozen pond. If ice friction and air resistance are neglected, the force needed to keep the puck sliding at constant velocity is

0 N

An object travels 8 m in the 1st second of travel, 8 m again during the 2nd second of travel, and 8 m again durign the 3rd second. Its acceleration is

0 m/s^2

If you toss a ball straight upward at 40 m/s with no air resistance, one second after it reaches the top of its path its speed is

10 m/s

The acceleration of a vertically thrown ball at the top of its path is

10 m/s

The gain in speed each second for a freely falling object is about

10 m/s

A push on a 1-kilogram brick accelerates the brick. Neglecting friction, to equally accelerate a 10-kilogram brick requires the force to be...

10 times as much.

A 10-kg mass at Earth's surface weighs about...

100 N.

Ten seconds after starting from rest, a freely falling baseball will have a speed of about

100 m/s

While in an airplane flying at 100 km/h you look down from the window and spot another airplane flying at the same speed in the opposite direction. Relative to you, the speed of the spotted plane is

200 km/h

Burl and Paulf have a total weight of 1300 N. The tensions in the ropes that support the scaffold they stand on add to 1700 N. The weight of the scaffold itself must be

400 N

The force of friction on a sliding object is 50 N. The applied force needed to maintian a constant velocity is

50 N

In a dream you're inn a car traveling at 50km/h and you bump into another car traveling toward you at 48km/h. The speed of impact is...

98 km.h

Compared with a 1-kg block of solid iron,, a 2-kg block of solid iron has the same...

All of the above 1. mass 2. weight 3. volume

The equilibrium rule, "E"F = 0, applies to

BOTH 1. objects or systems at rest. 2. objects or systems in uniform motion in a straight line.

If gravity between the Sun and Earth suddenly vanished, Earth would move in

a straight-line path

If the mass of an object does not change, a constant net force on the object produces constant

acceleration

Newton's second law focuses on

acceleration

When you stand at rest on a pair of bathroom scales, the readings on the scales will always

add to equal your weight

Which has zero acceleration?

all of the above 1. an object moving at constant speed 2. an object in mechanical equilibrium 3. an object at rest

A heavy object and a light object in a vacuum are dropped at the same time from rest. The heavy object reaches the ground

at the same time as the light object

A ball tossed vertically upward reaches its highest point and then falls back to its starting point. During this up-and-down motion the acceleration of the ball is always...

directed downward.

Marie pushes horizontally on her desk, but not hard enough to get it moving. The friction force acting on the desk is

equal and opposite to her push

Burl and Paul on a sign-painting scaffold are in equilibrium, which means that the net upward supporting force of the vertical ropes is

equal and opposite to the combined weights of Burl, Paul, and the scaffold.

When a crate slides down an incline at a constant velocity, it is

in dynamic equilibrium

If an object's mass decreases while a constant force acts on it, the acceleration

increases

If you jump straight up while inside a fast moving train that gains speed, you land

slightly behind your original position.

The resistive force of friction occurs for

solids, liquids, and gases

The net force on an object is

the combination of all forces acting on it

Your weight is

the gravitational attraction between you and the earth

What did Galileo incorporate in his study of motion that Aristotle overlooked?

the role of time

A chunk of metal has a mas of 1 kg on Earth. If the same chunk were on the moon its mass would be

the same

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

the same amount as your pushing force

Phil Physiker standing at the edge of a cliff throws one ball straight up and another ball straight down, both with the same speed. Both ball hit the ground at

the same speed in different time

As an object freely falls, its

velocity increases

An object in motion tends to remain in motion

without the need of a force

When a rock thrown straight up reaches the exact top of its path, its velocity is

zero and its acceleration is 10 m/s^2

The acceleration of a Tesla, that maintains a constant velocity of 120 km/h over a time of one-half hour, is

zero because of no change in velocity

The force required to maintain an object at a constant velocity in free space is equal to...

zero.