Ch 4 MGH chapter quiz

A 60-kg women is riding a 20-kg bicycle. She experience 50 N of wind resistance while she is generating -55 N of force. She is also pushing on her handle bars with 20 N of force. Her acceleration is thus ____ m/s^2 forward

5/80

A 50 kg couch is pushed by a 600 N force rightward against a constant 200N force of friction directed leftward. The couch experiences an acceleration of 8 m/s^2 rightward

8

Which of the diagrams represent an object that has some acceleration in the vertical direction?

A C D F

A ball is falling to the Earth, Ignoring air resistance, which of the free-body diagrams shown in the figure is the correct diagram for the ball?

a

Which of the following objects has net external force on it?

A couch being pushed by a person at constant speed and direction A box sliding on the ice with uniform velocity A rock resting on a table A car driving in a straight line path on cruise control A couch being pushed on by a person, but couch is not moving

A spaceship traveling 100,000 m/s in deep space, not other planets or stars, runs out of fuel during its trip. Which of the following will happen?

The spaceship will continue traveling at 100,000 m/s

A car's tires push on the ground with- 150 N of force forward. If the tires do not slip,then ground pushes on the tires with __N of force forward. If there are no other horizontal force on the 1500 kg car, it will experience an acceleration of __ m/s^2 forward

150 0.1

a 20-kg rock on Earth (g=10m/s^2) would weigh ___ N on Earth. It would have a mass of ___ kg on the moon (g=1.6 m/s^2)

200 20

A box being pushed by a force results in an acceleration of 2 m/s^2. the force results in an acceleration of ___ m/s^2

4

Aristotle Galileo Newton

Based his theory off of observations of nature and claimed that objects required a force to applied to keep them in motion experiments and claimed that no force was needed to keep an object in motion, but rather a force was needed to halt an objects motion Built his theory of motion off of the work of others and developed a quantitative model that more fully described how object would react to a force.

Double the acceleration Quarter the acceleration Quadruple (4x) the acceleration Halve the acceleration

Double the mass Quarter the mass Quadruple the mass Halve the mass

To which of the following things would newton's laws apply?

Galaxies planets rocks on earth trucks Satellites in space rocks on mars airplanes

Double the acceleration Quarter the acceleration Quadruple (4x) the acceleration Halve the acceleration

Halve the mass Quadruple the mass Quarter the mass Double the mass

The upward normal force of a book resting on a table with its wight the force of a mule pulling on a cart and the force of the cart pulling back on the mule

The force must be equal and opposite because the objects is not accelerating and thus has no net force on it The force must be equal and opposite since they are an action/reaction pair of forces

A car has multiple force acting on it. Which of the following forces will contribute to its acceleration?

The force of the ground on the car The air resistance on the car

An apple is dropped and accelerates towards the ground. What forces cause the apple to accelerate?

The gravitational force

Put the following objects in order from greatest acceleration to least acceleration

a 10 kg object experiences 1000 N of force A 100 kg object experiences 1000 N of force A 20 kg objects experiences 100 N of force A 10,000 kg object experiences 10,000 N of force.

We would say Newton's laws are general because they apply to ___ objects, not just ones on Earth or just in the sky

any

A couch is pushed along a floor against friction at a constant velocity. A partial free-body diagram is shown in the figure on the right.

d

If you wish to increase an object's acceleration without changing the force on the object, you must ___ the object's mass

decrease

The figure on the right contains six free-body diagrams. Which of the diagrams represent an object that is at rest or in uniform motion

e b

A ball rolls down a straight incline ramp, increasing its speed along the way. At what position is the net force the greatest?

everywhere

When engineers send supply rockets to the international Space Station they can simply turn off the rocket is lined up and it will coast to a stop

false

according to Galileo, an object will not stop moving unless a ____ is applied to the object.

force

A skydiver reaches terminal velocity during her dive which statements are correct about her motion while she is traveling at terminal velocity?

the air resistance force is = in magnitude to her wight there is no net force acting on here she is no longer accelerating

An apple at rest on a table has two forces acting on it, the normal force and the gravitational force. The reaction force to the gravitational force is

the gravitational force of the apple on the Earth

A mule pulls a cart twice as heavy as the mule

the net force acting on the mule is less than the net force on the cart The acceleration of the mule is the same as for the cart

The acceleration due to gravity is the same for all objects

true