SCIENCE - Chapter 3

The metric unit of force preferred by scientists is the:
a. kilogram.
b. newton.
c. mima.
d. pound.

Weight is a force that depends on mass and:
a. friction.
b. gravity.
c. magnetism.
d. energy conservation

Which of the following forces is a contact force?
a. Gravity
b. Friction
c. Magnetism
d. Electricity

Which of the following is the largest unit of force?
a. Kilogram
b. Ounce
c. Pound
d. Newton

If an elephant has a mass of 2,000 kg, what is her weight on Earth? a. 0.0049 N
b. 204 N
c. 19,600 N
d. 43,100 N

Of the following measurements, the one that would be incomplete without giving a direction is:
a. time.
b. temperature.
c. length.
d. force.

On a vector drawing, Alexi decides to use a scale of 1.0 cm = 2.0 N. The force represented by an arrow 3.5 cm long would be:
a. 1.0 N
b. 2.0 N
c. 3.5 N
d. 7.0 N

Compared to your weight and mass on Earth, if you were on the moon:
a. your weight and mass would be less.
b. your weight would be less but your mass would remain the same.
c. your weight would remain the same, but your mass would be less.
d. your weight would increase, but your mass would remain the same.

Which pair of terms are vectors?
a. speed and mass
b. acceleration and force
c. velocity and speed
d. mass and weight

A force that resists the motion of an object moving across a surface is called:
a. static friction.
b. sliding friction.
c. rolling friction.
d. air friction.

What does a maglev train use to reduce friction?
a. Oil
b. Air cushion
c. Ball bearings
d. Water

A force that resists motion is called:
a. weight.
b. motion.
c. equilibrium.
d. friction.

Ball bearings decrease friction in rotating motion because:
a. they are made of hard steel.
b. they replace sliding friction with rolling friction.
c. they separate surfaces with a cushion of air.
d. they can be made in all sizes to fit different machines.

Which of the following would increase the sliding friction between your foot and the floor?
a. Increasing the weight on your foot.
b. Decreasing the weight on your foot.
c. Putting water between your foot and the floor.
d. Separating your foot and the floor

The tires on a car have grooves in them. How do these grooves affect the friction between the tires and the road during wet weather?
a. They increase friction.
b. They decrease friction.
c. They have no effect on friction.
d. They first decrease, then increase friction.

How can the force of friction between two surfaces be reduced?
a. By changing rolling friction to sliding friction.
b. By making smooth surfaces rougher.
c. By separating surfaces with a lubricant.
d. By increasing the force between the surfaces.

Which types of energy are released by the friction force between a car’s tires and the road during a skidding, squealing stop?
a. Heat and sound
b. Motion and friction
c. Nuclear and gravity
d. Lubrication and motion

If the net force on a moving object is zero:
a. the object will slow down and stop. b. the object will change direction.
c. the object will change speed.
d. the object will not change direction or speed.

True or false.
-Weight- is a force from gravity pulling down on any object with mass.

True or false.
By compressing a spring, you -increase – its length.

True or false.
The greater the force squeezing 2 surfaces together, the -smaller- the friction force.

True or false.
A -zero- net force causes an acceleration.

True or false.
Force is the ability to change motion.

True or false.
Tension is a contact force.

If you traveled to Mars, your mass would be _________________________ than your mass on Earth.

The _________________________ is the English unit of weight equal to about 0.454 kg of mass.

A force that resists the motion of objects or surfaces as they move over one another is called ____________________.

A diagram shows all the forces acting on an object is a _________________________ diagram.

Force is a(n) ____________________ because it has both an amount and a direction.

The metric unit of force required for a 1-kg object to accelerate at 1 m/s2 is the _________________________.

Describe one similarity and one difference between friction and gravity.

Explain how the same object could weigh 50 pounds on Earth and 8.3 pounds on the moon.

If there were no friction, we could not walk. Explain why friction is necessary for walking.

What does it mean when the net force on an object is zero?

A toddler weighs 30.0 pounds. If 1.00 newton equals the weight of 0.228 pounds, what is the weight of the toddler in units of newtons?

Two body builders are involved in a weight lifting contest to determine who is the stronger. Ivan lifts 500 pounds. Vladimir lifts 2000 newtons. Who is stronger?

When trying to slide an object, it is generally easier to keep the object moving than it is to start the object moving. Explain why this is so including the terms static and sliding friction in your explanation.

What does the “G” stand for in the law of universal gravitation equation?

Geocrynconized orbit

What does it mean to triangulate your signal?

True or false.
All satellites are in geocyncronized orbit.

Conservation Momentum

What is the unit for momentum?

What is the unit for velocity?

What is the unit for net force, weight, and friction?

What is the unit for acceleration?

What is the equation for collision?

True or false.
As a skateboard increases her speed (in velocity) from 2 m/s to 4m/s, she also increases her -inertia-.

True or false.
“For every action there is an equal and opposite reaction’ is a statement of Newton’s first law of motion.

True or false.
Units for measuring impulse, newton-seconds, are equivalent to kilogram-meters per second, units for measuring momentum.

Forces occur in pairs is another way of stating Newton’s _____ law of motion.

A rocket can fly into space because:
a. the exhaust gases push against the ground and the ground, in turn, pushes the rocket
b. the rocket pushes on exhaust gases and the exhaust gases push back on the rocket
c.as the fuel burn, the rocket’s mass decreases reducing the force of gravity on the rocket
d. the launch pads absorbs momentum that it imparts to the rocket

What is the equation to calculate momentum?

As the speed of a rolling ball is increasing the increasing speed is accompanied by
a. increasing momentum
b. increasing inertia
c. decreasing momentum
d. both increasing inertia and momentum

The impulse applied to an object is equal to the change in the objects
a. mass
b. inertia
c. momentum
d. height

To increases the final momentum of a racquetball, the player should:
a. swing the racquet as fast as possible
b. follow through when hitting the ball
c. increase contact time with the ball
d. all of the above

The momentum of a 2000 kilogram car traveling at 20 meters per second is:
a. 0 kg x m/sec.
b. 0.001 kg x m/sec.
c. 100 kg x m/sec.
d. 40,000 kg x m/sec.

If a 40,000 kilogram rocket were traveling from its launch pad at a speed of 150 meters per second, 800 kilograms of gases would be expelled from the rocket at a speed of about:
a. 0.33 m/sec.
b. 270 m/sec.
c. 7,500 m/sec.
d. 21,000 m/sec.

While standing on a stationary skateboard, Jolene tosses a heavy ball horizontally toward one end of her skateboard. The skateboard moves. Assuming there is no friction in the system when the ball is tossed, which statement about the momentum of the heavy ball is INCORRECT?
a. The ball’s momentum is equal in size to the momentum of Jolene and her skateboard.
b. The ball’s momentum plus the momentum of Jolene and her skateboard equals zero.
c. The ball’s momentum has increased because Jolene has tossed it.
d. The directions of the ball’s momentum and Jolene’s momentum are the same.

An object falls without friction near Earth’s surface. The loss of its potential energy is equal to its:
a. loss of height.
b. loss of mass.
c. gain in kinetic energy.
d. gain in velocity.

Even though every action force has an equal but opposite reaction force, they do not cancel one another and motion may still occur because the:
a. action and reaction forces are applied to the same object.
b. action and reaction forces are applied to different objects.
c. two forces have different magnitudes.
d. two forces have equal magnitudes.

Which of the following situations is an example of a mostly elastic collision?
a. Two billiard balls collide and bounce off each other.
b. Two train card collide and stick together.
c. When a soft piece of clay falls onto the floor, its shape flattens.
d. A glass falls off the table and breaks.

Energy that is stored due to the position of an object may be called ____ energy.
a. kinetic
b. potential
c. radiant
d. nuclear

The ability to cause change is defined as:
a. force and is measured in newtons.
b. power and is measured in watts.
c. energy and is measured in joules.
d. impulse and is measured in newton-seconds.

A 0.15-kilogram baseball thrown at a speed of 50 meters per second and a 7.25-kilogram bowling ball rolling at 2 meters per second are both stopped in 0.2 seconds.
a. The baseball is stopped with less force because it has less inertia.
b. The baseball is stopped with less force because it has less momentum.
c. The bowling ball is stopped with less force because it has less momentum.
d. The bowling ball is stopped with less force because it has less inertia.

Kiki accidentally nudges a glass tumbler with her elbow and it falls toward a hard, ceramic tile floor. As a soccer player, Kiki reacts by catching the glass with her foot and lowering it to the floor, preventing the glass from breaking. Her action prevents the breakage because:
a. the change in momentum is smaller when Kiki catches and lowers the glass to the floor.
b. the impulse is smaller when Kiki catches the glass and lowers it to the floor.
c. the time interval for stopping is greater when Kiki catches the glass with her foot.
d. a larger force is exerted by Kiki’s foot to stop the glass in time.

The skateboard on which you are standing moves as one of your feet pushes on the ground because the force you apply on the skateboard:
a. equals the force applied to you by the skateboard.
b. is larger than the force applied to you by the skateboard.
c. equals the force applied by the ground on the skateboard.
d. is larger than the force applied by the ground on the skateboard.

A 20-kilogram object falls 2.0 meters to the floor. At what point in its fall does the kinetic energy of a body equal its potential energy?
a. At all points of the fall
b. Very nearly at the top of the fall
c. Halfway to the floor
d. Just the instant before it hits the floor

As the speed of a moving object doubles, the amount of mechanical kinetic energy that it possesses:
a. increases by two times.
b. increases by four times.
c. decreases by two times.
d. decreases by four times.

In science, work is defined as:
a. the mass of an object multiplied by its acceleration.
b. the mass of an object multiplied by the force required to move it.
c. force multiplied by the distance moved in a direction perpendicular to the force.
d. force multiplied by the distance moved in the same direction as the force.

To increase the final momentum of a racquetball, the player should:
a. swing the racquet as fast as possible.
b. follow through when hitting the ball.
c. increase contact time with the ball.
d. All of the above

Calculate the work done to lift a barbell weighing 100 newtons a distance of 1.5 meters.
a. 0.015 joules
b. 15 joules
c. 66.7 joules
d. 150 joules

A 2-kilogram piece of clay moving at 4 m/sec strikes and sticks to a second 4-kilogram piece of clay moving at 1 m/sec in the opposite direction. Calculate the speed of the combined piece of clay.
a. 1 m/sec
b. 2 m/sec
c. 4 m/sec
d. 6 m/sec

All of the following may be the result of an inelastic collision EXCEPT:
a. permanent change in the shape of the colliding bodies.
b. kinetic energy released as sound.
c. colliding bodies stick to one another.
d. zero loss of kinetic energy.

Air bags reduce injury in automobile accidents by:
a. reducing the time of collision.
b. reducing the change in momentum.
c. increasing the applied force.
d. increasing the time of collision.

Lifting a 70-kilogram barbell 2.0 meters above the floor increases its potential energy by about:
a. 35 joules.
b. 140 joules.
c. 350 joules.
d. 1,400 joules.

A boy whose mass is 40 kilograms runs at 5 meters per second and jumps onto a 10-kilogram stationary sled. The boy slides on the sled over a horizontal, frictionless surface at a speed of:
a. 2 m/sec.
b. 4 m/sec.
c. 5 m/sec.
d. 10 m/sec.

The amount of mechanical kinetic energy possessed by a 0.25-kilogram ball rolling at a speed of 2.5 meters per second is ____ joules.
a. 0.31
b. 0.63
c. 0.78
d. 1.6

Potential energy increases as a marble:
a. slows rolling up an incline.
b. increases speed down an incline.
c. rolls at uniform speed on a level table.
d. sits motionless on the floor.

When two objects hit each other a _______ occurs.

Ken rolls a 7-kilogram bowling ball so slowly that it stops before it moves through all of the pins. The impulse necessary to stop this bowling ball rolling at 2 meters per second is ____ newton-seconds.
a. 3.5
b. 5.0
c. 7.0
d. 14

What braking force is needed to stop a 1,000-kilogram car moving at 10 m/sec in a time of 1 seconds?
a. 1 newton
b. 10 newtons
c. 100 newtons
d. 10,000 newtons

As Maria steps from a small rowboat towards a pier, the boat moves away from the pier. Maria falls into the water. She is a “victim” of the law of conservation of ____________________.

The expression 1/2 mv^2 represents ____________________ energy.

The expression f x t represents _________________________.

“Energy can never be created or destroyed, just transformed from one form to another” is a statement of the law of ______________________________ (three words).

Alicia is asked to calculate the change in momentum that occurs as she stops her bicycle. This is equivalent to the ____________________ applied to the bicycle.

The kinetic energy of an object depends upon two things: ____________________ and ____________________.

The expression mgh represents _________________________ energy.

Alex hits a line drive directly up the middle which leaves his bat traveling at 250 meters per second. If the pitcher has thrown the 0.15-kilogram baseball to Alex at 140 meters per second, what is the impulse applied to the baseball by Alex?
a. 17 newton-seconds
b. 21 newton-seconds
c. 38 newton-seconds
d. 50 newton-seconds

What impulse must be applied to a 3-kilogram object to give it 150 joules of kinetic energy?
a. 21 newton-seconds
b. 30 newton-seconds
c. 50 newton-seconds
d. 3,000 newton-seconds

Jumping on a tramp line, Jeffrey can easily soar 6 feet into the air but can only jump 2 feet from the blacktop of the driveway basketball court because the:
a. court applies a larger impulse
b. trampoline applies a larger impulse
c. court applies less force on Jeffrey
d. trampoline applies more force on Jeffrey

Work may be measure using the units of?
a. watts
b. newtons
c. joules
d. newtons per second

Jonah is pushing his young sister, Jessica, on a swing. If Jessica weighs 350 newtons, how much higher above the ground must Jonah push her to increase her potential energy by 525 joules?
a. 0.67 meters
b. 1.5 meters
c. 3.6 meters
d. 5.4 meters

The amount of kinetic energy possessed by a 0.25-kilogram ball rolling at a speed of 2.5 meters per second is ______ joules.
a. 0.31
b. 0.64
c. 0.78
d. 1.6

When the brakes are fully applied, compares to the distance required to stop a car going 30 miles per hour, the distance needed to stop a car going 90 miles per hour is:
a. 3 times as great
b. 6 times as great
c. 9 times as great
d. the same

A speeding truck makes contact with a bug on its windshield. Compare the force that the bug exerts on the truck to the force the truck exerts on the bug.

When you push on your friend who is seated in a wagon, the wagon moves. According Newton’s 1st law of motion, the force you apply to your friend is equal but opposite to the force your friend applies to you. Explain why the two equal and opposite forces do not cancel one another with no resulting motion. tell what foes does cause the motion.

As a tennis player, golfer, baseball player or soccer player yu might be told by your coach to “follow through” when stiking the ball. Explain why.

Calculate the momentum of a 30-kilogram cart moving at a speed of 2.0 meters per second.

While sitting motionless on a 10-kilogram, friction-free wagon, 75-kilogram “Bozo, the human target” catches an 8-kilogram cannonball moving at 15 meters per second. After cathing the cannonball, at what speed do Bozo, the wagon and cannonball move?

Calculate the size of the impulse that must be applied to stop a 200-kilogram wagon rolling on a flat path at a speed of 4.5 meters per second.

Calculate the maximum height a 0.75-kg ball will rise if it is kicked straight up with an initial speed of 17 meters per second.

Give me an example of static friction.

Give me an example of kinetic friction.

Is a car moves at a constant velocity, the forces are balanced because there is no _________.

____ ______ causes acceleration.