Physics 1050 Chpt. 2,3,4,5

the component of velocity that can remain in constant for a tossed baseball is

horizontal

When a tin can is whirled in a horizontal circle the net force on the can acts

inward

2 carts: one twice as massive as the other, fly apart when the compressed springs between them is released. What is the acceleration of the heavier cart to that of the lighter cart as they start to move apart ?

mA=Ma

The team that wins in a tug-of-war is the team that

pushes hardest on the ground

A big fish swims upon and swallows a small fish that is at rest, right after lunch the fattened big fish has a change in

speed

An object in free fall undergoes an increase in

speed

Terminal Velocity

terminal speed together with the direction of motion

Static Friction

the force between two objects that are at relative rest by virtue of contact that tend to oppose sliding

A 10-N force at an angle of 45 degrees above the horizontal has a horizontal component of about

7-N

The equilibrium rule (zeta F=0) applies to objects

Object at rest and in constant velocity

Inertia

Property of an object to resist changes in motion

Different scaffold that weighs 400-N supports two painters one 500-N & other 400-N. The reading on the LT scale is 800-N. What is the reading on the RT scale

RT side tension has to be 500-N 500-N+400-N+400N The system is in static equilibrium

Consider the two forces acting on the person who stands still-namely the downward pull of gravity and the upward support of the floor. Are these forces equal and opposite? Do they form an action reaction pair?

The person is not moving, forces are opposite and equal. Does not form a action reaction pair.

Correct your friend who says, "the dragster rounded the curve at a constant velocity of 100 km/h."

cannot be in constant velocity and change direction

The amount of air drag on a 0.8-N flying squirrel dropping vertically at terminal velocity is

0.8-N

The average speed of a gazelle traveling a distance of 2-km in a time of one half hour is

4 km/h

Two vectors, one 3-N and the other 4-N can have a resultant of

5-N

An airplane with its nose pointing north with an airspeed of 40 km/h in a 30 km/h crosswind (at right angles) has a ground speed of

50 km/h

Each bone in the skeletal chain of bones forming your spine is separated from its neighbors by disks of elastic tissue. What happens then when you jump heavily on to your feet from a elevated position ?

Bits of bone continue to move down until all comes to rest

If you toss a coin straight upward while riding in a train where does the coin land when the motion of the train is uniform along a straight line track? When the train slows while the coin is in the air ?

Coin in movement will stay straight up and come straight down relative to you

In terms of N-1st law, how does a car headrest help to guard against whiplash in a rear end collision

Force of car VS head rest VS pivot that head wants to stay at rest

2 people standing on scales playing tug-of-war. Will the scale readings differ ?

NO, rope has net zero force

How does Newtons first law of motion relate to Galileo's concept of inertia

Newton's law is a restatement of Galileo's concept of inertia

Asteroids have been moving through space for billions of years. What keeps them moving

Newtons 1st law : Inertia

The fact that the acceleration of free fall is the same for all masses is explained by Newtons

Newtons 2nd Law

The impulse-momentum relationship is a direct result of Newtons

Newtons 2nd Law

If gravity between the sun and Earth suddenly vanished Earth would continue moving in

a straight line

A 10-N falling object encounters 4-N of air resistance. The net force on the object is

a) 0-N b) 4-N c) 6-N d) 10-N e) none of these answer:c

A jumbo jet has a mass of 100,000-kg. The thrust for each of its four engines is 50,000-N. What is the jets acceleration in meters per second per second when taking off

a) 0.25 b) 1 c) 2 d) 4 e) none of these answer:c

An object at rest near the surface of a distant planet start to fall freely. If the acceleration there is twice that of the earth, its speed one second later would be

a) 10m/s b) 20m/s c) 30m/s d) 40m/s answer:b

A horse gallops a distance of 10-km in a time of 30 minutes. Its average speed is

a) 15 km/h b) 20 km/h c) 30 km/h d) 40 km/h answer:b

If a car accelerates from rest at 2 meters per second per second its speed 3 seconds later will be about

a) 2 m/s b) 3 m/s c) 4 m/s d) 6 m/s answer:d

If a car increases its velocity from zero to 60 km/h in 10 seconds, its acceleration is

a) 3km/h/s b) 6km/h/s c) 10km/h/s d) 60km/h/s e) 600km/h/s answer:b

If a freely falling object were somehow equipped with a speedometer its speed reading would increase each second by about

a) 5 m/s b) 10 m/s c) 15 m/s d) a variable around e) depends on its initial speed answer: b

Arnold Strongman and Suzie Small each pull very hard on opposite ends of a massless rope in a tug-of-war. The greater force on the rope is exerted by

a) Arnold of course b) Suzie, surprisingly c) both the same, interesting enough answer:c

The human body can under certain conditions, with stand an acceleration of 10-g. What net force would produce this acceleration of a 50-kg person

a) about 500-N b) about 2500-N c) about 5000-N d) about 25,000-N e) none of these answer:c

It takes 6 seconds for a stone to fall to the bottom of a mine shaft. How deep is the shaft ?

a) about 60m b) about 120m c) about 180m d) more that 200m answer:c

As a ball falls, the action force is the pull of the Earth on the ball. The reaction force is the

a) air resistance acting against the ball b) acceleration of the ball c) pull of the ball's mass on the Earth d) none of these answer:c

For an action force, there must be a reaction force that

a) always acts in the same direction b) is slightly smaller in magnitude than the action force c) is slightly larger in amplitude than the action force d) is exactly equal in magnitude answer:d

An object in mechanical equilibrium is an object

a) at rest b) moving with constant velocity c) having no acceleration d) all of these answer:d

Whirl a rock at the end of a string and it follows a circular path. If the string breaks, the tendency of the rock is to

a) continue to follow a circular path b) follow a straight line path c) increases its speed d) revolve in a a smaller circle answer:b

The force to keep a ball rolling along a bowling alley is

a) due to gravity b) inertial force c) slight breeze d) none of these answer:d

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

a) each be half your weight b) each equal your weight c) add up to equal your weight answer:c

The force exerted on the tires of a car to directly accelerate it along a road is exerted by the

a) engine b) tires c) air d) road e) none of these answer:d

A truck is moving at constant velocity. Inside the storage compartment a rock is dropped from the midpoint of the ceiling and strikes the floor below. The rock hits the floor

a) exactly below the midpoint of the ceiling b) ahead of the midpoint of the ceiling c) behind the midpoint of the ceiling d) more information is needed to solve this problem e) none of these answer:a

An object is propelled along a straight line path by a force. If the net force were doubled, the objects acceleration would be

a) half as much b) the same c) twice as much d) four times as much e) none of these answer:c

A ball tossed vertically upward rises, reaches it highest point, and then falls back to its starting point. During this time the acceleration of the ball is always

a) in the direction of motion b) opposite its velocity c) directed upward d) directed downward answer:d

A heavy block at rest is suspended by a vertical rope. When the block is accelerated upward by the rope, the rope tension

a) increases b) decreases c) remains the same answer:a

If one object has twice as much mass as another object. it also has twice as much

a) inertia b) velocity c) acceleration due to gravity d) volume e) all of these answer:a

The force of friction on a sliding object is 10 N. The applied force needed to maintain a constant velocity is

a) more than 10 N b) less than 10 N c) 10 N answer:c

An object is propelled along a straight line path in space by a force. If the mass of the object somehow becomes twice as much, its acceleration

a) quadruples b) doubles c) stays the same d) halves e) none of these answer:d

Strange as it may seem, it is just as hard to accelerate a car on a level surface on the moon as it is here on Earth. This is because ...

a) the mass of the car is independent due to gravity b) the weight of the care is independent to gravity c) nonsense ! a care is much for easily accelerated on the moon than the Earth answer:a

The attraction of a person's body toward the Earth is called weight. The reaction to this force is

a) the person's body pushing against Earth's surface b) the Earth's surface pushing against the person's body c) there person's body pulling on the Earth d) none of these answer:c

When a model car speeds up to three times its original speed its kinetic energy is

a) the same b) twice as great c) three times greater d) none of these answer:d

A feather and a coin will have the equal acceleration when falling in a vacuum because

a) their velocities are the same b) the force of gravity is the same for each in a vacuum c) the force of gravity does not act in a vacuum d) the ratio of each objects weight to its mass is the same e) none of these answer:d

If an object of constant mass experiences a constant net force, it will have a constant

a) velocity b) speed c) acceleration d) position e) more than one of the above answer:c

A mack truck and a volkswagon traveling at the same speed have a head-on collision. The vehicle undergoes that greatest change in velocity will be the

a) volkswagon b) mack truck c) same for both answer:a

A kilogram is a measure of an object's

a) weight b) foce c) mass d) size answer:c

A car maintains a constant velocity of 100 km/hr for 10 seconds. During this interval its acceleration is

a) zero b) 10km/hr c) 110km/hr d) 1000km/hr answer:a

A rock is thrown vertically into the air. At the top of its path, its acceleration in meters per second per second is

a) zero b) 9.8 c) between 0 & 9.8 d) greater than9.8 answer:b

A package falls off a truck that is moving at 30 m/s. Neglecting air resistance the horizontal speed of the package just before it hits the ground is

a) zero b) less than 30 m/s but larger than zero c) about 30 m/s d) more than 30 m/s e) more information is needed for an estimate answer:c

A Karate chop delivers a blow of 3000-N to a board that breaks. The force that acts on the hand during this event it

a) zero b) 1500-N c) 3000-N d) 6000-N answer:c

the magnitude of the gravitational force on a satellite is constant if the orbit is

circular

Consider a vertically launched projectile when air drag is negligible. When is the acceleration due to gravity greatest: when ascending, at the top, when descending

acceleration due to gravity remains a constant (g) at all points along its path as long as no other forces like air drag act on the projectile

When a cannonball is fired from a cannon both the cannonball and cannon experience equal

amounts of force

A satellite in Earth orbit is above Earth's

atmosphere

The rotational inertia of an object is greater when most of the mass is located

away from the axis

3 identical blocks pulled horizontally frictionless surface tension in the rope held by the hand at 30-N. What is the tension in the ropes ? block-----t3-----block----t2----block----30-N---->

block----10-N----block----20-N----block----40-N--->