Physics Questions: Newton's Laws and Forces, Study notes of Physics

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(1)Read Ch. 4 – Forces and Newton's laws

1 A body in uniform motion remains in uniform

motion, and a body at rest remains so, unless acted

on by a nonzero net force.

3 For every action there is an equal and opposite

reaction.

F

net

=m a

F

F

Newton's Laws

A woman pulls on a 6.00-kg crate, which in turn is connected to a 4.00-kg crate by a light rope. The light rope remains taut. Compared to the 6.00–kg crate, the lighter 4.00-kg crate A. is subjected to the same net force and has the same acceleration B. is subjected to a smaller net force and has the same acceleration C. is subjected to the same net force and has a smaller acceleration D. is subjected to a smaller net force and has a smaller acceleration E. none of the above

In problem 4.47 an airplane pulls two gliders.

The airplane produces forward thrust F_p from its

propeller. What is the thirdlaw couple for F_p?

a Backward tension in tow rope connected to

plane.

b Backward force on atmosphere from propeller.

c Backward force on airplane from drag.

d Gravity

In problem 4.47 an airplane pulls two gliders.

The airplane produces forward thrust F_p from its

propeller. What is the thirdlaw couple for F_p?

a Backward tension in tow rope connected to

plane.

b Backward force on atmosphere from propeller.

c Backward force on airplane from drag.

d Gravity

You are pushing a 1.00- kg food tray through the cafeteria line with a constant 9.0-N force. As the tray moves, it pushes on a 0.50-kg milk carton. A. the tray exerts more force on the milk carton than the milk carton exerts on the tray B. the tray exerts less force on the milk carton than the milk carton exerts on the tray C. the tray exerts as much force on the milk carton as the milk carton exerts on the tray Q4. QuickTimee and aﾪ TIFF (LZW) decompressor are needed to see this picture. If the food tray and milk carton are accelerating to the left ,

The motion diagram shows an object moving along a curved path at constant speed. At which of the points A, C, and E does the object have zero acceleration? A. point A only B. point C only C. point E only D. points A and C only E. points A, C, and E

Q

An object moves at a constant speed in a clockwise direction around a circular track. The geometrical center of the track is at point O. When the object is at point P , which arrow shows the direction of the object’s acceleration vector? A. arrow #1 (directly away from O ) B. arrow #2 (perpendicular to track) C. arrow #3 (in direction of motion) D. arrow #4 (directly toward point O )

P

O

o v a l t r a c k Q3.4a

An object moves at a constant speed in a clockwise direction around a circular track. The geometrical center of the track is at point O. When the object is at point P , which arrow shows the direction of the object’s acceleration vector? A. arrow #1 (directly away from O ) B. arrow #2 (perpendicular to track) C. arrow #3 (in direction of motion) D. arrow #4 (directly toward point O )

P

O

o v a l t r a c k A3.4a

Science teachers ride the vomit comet http://www.youtube.com/watch?v=iCAzo-wTxiU&NR=

Astronauts in orbit are weightless because:

a gravity ends at the edge of Earth's atmosphere.

b they are too far from the center of Earth for

gravity to affect them much.

c they are closer to the moon which mostly

balances Earth's pull.

d they aren't weightless, they're just falling.

e there are good special effects on that “space

set” in Arizona that NASA has been using for years.