45 terms

An educated scientific guess is a

Hypothesis

For a scientific hypothesis to be valid, there must be a test for proving it

Wrong

Inertia is defined as a

Property of matter

If no external forces act on a moving object, it will

Continue moving at the same speed

A force is a vector quantity because it has both

Magnitude and direction

A block pulled to the left with 15N and to the right with 5N at the same time experiences a net force of

10N

An object in mechanical equilibrium is an object

At rest, moving with constant velocity and having no changes in velocity

Burl and Paul have a total weight of 1300N. The tensions in the supporting ropes that support their scaffold add to 1700N. The weight of the scaffold itself must be

400N

The net force on any object in equilibrium is

zero

The support force on a 10N book at rest on a table is

10 N

An 800-N man stands at rest on two bathroom scales so that his weight is distributed evenly over both scales. The reading on each scale is

400 N

Earth continually moves about 30 km/s through space, which means the wall you stand next to also is moving at 30 km/s. When you jump vertically the wall doesn't slam into you because

You're moving horizontally just as fast as the wall

The newton is a unit of

Force

A kilogram is a measure of an object's

Mass

1-kg mass at the Earth's surface weighs

10 N

Compared to the mass of an apple on Earth, the mass of the apple on the Moon is

The same

The speedometer of an automobile reads

instantaneous speed

The two measurements necessary for calculating average speed are

Distance and time

When you walk at an average speed of 4 m/s, in 5 s you'll cover a distance of

20 m

A freely-falling watermelon falls with constant

acceleration

The distance a freely falling bowling ball falls each second

increases

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

10 N

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

6 N

If the mass of a cart is quickly loaded to have twice the mass while a propelling force remains constant, the cart's acceleration

Halves

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

Is greater than its weight

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

2000N

Neglecting friction, a small and a large block of ice begin sliding down an incline together. The larger block reaches the bottom

At the same time as the small block

When a falling object has reached its terminal velocity, it's acceleration is

Zero

A light woman and a heavy man jump from an airplane at the same time and open their same-size parachutes at the same time. Which person will get to the ground first?

The heavy man

A skydiver's terminal velocity will be greatest if she falls

Head first

A 500-N parachutist opens his chute and experiences an air resistance force of 800 N. The net force on the parachutist is then

300 N upward

According to Newton, the greater the masses of interacting objects, the

greater the gravitational force between them

According to Newton, when the distance between two interacting objects doubles, the gravitational force is

One-quarter

In comparison with other fundamental forces, the universal gravitational constant G indicates that gravity is

very weak

If the Sun collapsed to a black hole, Earth's gravitational attraction to it would be

the same

Accelerate an electron and you produce an electromagnetic wave. Accelerate a massive body and you produce

a gravitational wave

Einstein's theory of gravitation

Agrees with established results of Newton's theory, incorporates Newton's theory as a special case, has been supported by repeated experiments, and is superior to newton's where space time is more curved.

You cannot exert a force on a wall

unless the wall simultaneously exerts the same amount of force on you

The winner in a tug-of-war exerts the greatest force on

The ground

A pair of action-reaction forces always

occur simultaneously

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

is equal in magnitude

A player hits a ball with a bat. If action is the force of the bat against the ball, reaction is the

force that the ball exerts on the bat

Joshua is attracted toward Earth by a 500-N gravitational force. The Earth is attracted toward Joshua with a force of

500-N

The force that propels a cannonball when fired from a cannon is

equal and opposite to the force the ball exerts on the cannon

When a cannonball is fired from a cannon, which undergoes the greater acceleration?

the cannonball