Scen 101 - Exam 1 Questions

A machine puts out 100 W of power for every 1000 W put in. The efficiency is

10%

What is the weight of the water displaced by a 100 ton floating ship?

100 tons

Escape speed from Earth is

11.2 km/s

A tow truck exerts a force of 3000 N on a car that accelerates 2 m/s^2. The mass of the car must be

1500kg

A shopping cart moves with a KE of 40 J. If it moves twice its speed, KE is

160J

Fido weighs 120 N and carries Trixie who weighs 40 N on his back. The support force Fido feels is

160N

A girl pushes a cart to the left with a 100 N force A boy pushes it to the right with a 50 N force. The net force exerted on the cart is

50N to the left

Which of the following has the greatest momentum relative to Earth?

a pickup truck speeding along a highway

An umbrella tends to jerk upwards on a windy day principally because

air pressure is reduced over the curved top surface

Which of these is a scientific hypothesis?

an atom is the smallest bit of matter in a material

As water in a confined pipe speeds up, the pressure it exerts against the inner walls of the pipe

decreases

If a loaf of bread is compressed

density increases

A given net force propels an object along a straight line path. If net force doubles, its acceleration would

double

A parachutist falling at constant velocity is in

dynamic equilibrium

Successes in science is mainly linked to emphasis on

experiments

According to Newton, greater masses of interacting objects,

greater gravitational force

Scientific equations in a conceptual course are mainly

guides to thinking about the relationship between concepts

Lifting 100 N load with 50 N force lifts it

half as high

A ball rests in the middle of a cart. When you quickly jerk the cart forward, the ball

hits the back of the cart

In science, an educated guess is a

hypothesis

In a vacuum, a marshmallow becomes

larger

The lunar month is 28 days. If the moon were closer to Earth than it is now, the lunar month would be

less than 28 days

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

road

A mack truck and a mini cooper travelling at the same speed collide head on. The collision force is greater on the

same

Which requires more work on car brakes?

slowing down from 100 km/h to 70 km/h

The statement "there are regions of earth's crust beyond investigation" is

speculation

A moving object has

speed, momentum, velocity, energy

Whirl a rock at the end of a string and it will follow a circular path. If the string breaks, it will continue in a

straight line path

The ultimate source of energy from fossil fuels is from the

sun

In science, a theory is a

synthesis of a large body of well tested knowledge

A truly educated person is knowledgeable about

the arts, science, religion (all of the above)

Exert 100 J in 50 s and your power output is

2 W

A car has a mass of 1000 kg and accelerates at 2 m/s^2. What is the force?

2000N

If a projectile is fired straight up at a speed of 10 m/s, neglecting air resistance, the total time to return to its starting position is

2s

A girl pulls on a 10 kg wagon with a constant force of 30 N. What's the wagon's acceleration?

3 m/s^2

A 3000 N bear grasping a vertical tree slides down at constant velocity. The friction force between the tree and the bear is

3000N

A karate chop breaks a board with a force of 3000 N. The force acting on the hand is

3000N

If a ball rolls down an inclined plane and picks up 4 m/s each second it rolls, acceleration is

4 m/s^2

A projectile is thrown into the air at an angle of 50 degrees and lands on a target that is at the same level the projectile started. With no air resistance it will also land on the target if it is thrown at an angle of

40 degrees

Aristotle believed natural laws are understood by

logic

In contrast to Aristotle's way of explaining nature, Galileo relied on

logic

A kilogram measures

mass

The language of science is

mathematics

If the masses of two planets double and the distance between them reduces by half, the force between them would be

none of the above - answer on exam 16 times greater - numerical answer

A scientific hypothesis can be disproved with

one reproducible experiment

When you stand on a scale on your tiptoes, there's an increase in

pressure on the scale, not registered as weight

Compared to a bar of pure gold, density of a gold ring is

the same

Compared to the buoyant force of the atmosphere on a 1-L helium balloon the buoyant force on a 1-L solid iron block is

the same

A car travelling at 100 km/h strikes an unfortunate bug that splatters on a windshield. The force of impact is greater on

the same for both

Atmospheric pressure is caused by

the weight of the atmosphere

In order to catch a softball w your bare hand, extend hand forward and ride back w ball. Doing this reduces catching force because

time of catch is increased

When you push your desk to the right, friction is acting

to the left

Suspend a pair of ping pong balls from two strings so there is a small space between them. If you blow air between them, they will swing

towards each other

If you push an object twice as far while applying same force, you do

twice the work

A change in pressure at any point in a confined fluid at rest is transmitted

undiminished to all points in the fluid

Passengers in a high flying jumbo jet feel their normal weight in flight. Passengers in an orbiting space vehicle do not because passengers are

without support forces

An object in motion stays in motion

without the need of a force

A mack truck and a mini cooper travelling at the same speed collide head on. The collision force is greater on the

wood

A hypothesis that is scientific must have a test proving it

wrong

Whenever net force is zero, acceleration is

zero