Forces
Types of Forces
Gravity
Electromagnetism
100

What is a force?

is a push or pull on an object

100

Which types of forces are exerted on a boat as it moves through water?

drag and normal force

100

True and False.

A force of gravity exists between any two objects having mass.

True

100
The most common way to spin the rotor of a generator is to attach it to the machine called a/an___ that has fanlike blades.

Turbine

200
The metric unit of force is the ___.

Newton

200

which of the following forces are contact forces?

friction and tension

200
Which of the following would most increase the force of gravity between two objects?

A. Doubling the distance between them

B. Doubling the mass of each object.

C. Doubling the distance between them and doubling the mass of each object.

D. Halving the distance between them and doubling the mass of each object.

D.

200

Which two kinds of electrical generating plants rely on water to spin a turbine?

hydroelectric and tidal

300

A force adds ___ to an object.

Energy

300

In which of the following examples is work being done on an object?

A. A boy throws a football ten years downfield.

B. A child presses down on a tabletop.

C. A girl lifts a book from a lower shelf to the top shelf in a bookcase.

D. A women rocks her baby to sleep.

A, C, D

300

A feeling of weightless in space is caused by ___.

Microgravity

300

How are electricity and magnetism related?

A moving electric current can generate a magnetic field, and a moving magnetic field can produce an electric current.

400

True or false.

A force is needed to change an object's motion. 

True

400

In forces acting on an object do not change the object's motion, then the forces must be __.

balanced

400

Is it correct to say that scientists understand gravity?

No
400

In an electric generator, the part that spins is called the ___ and the part that doesn't move is called ___.

Rotor; Stator

500

Which type of forces can change an object's motion, balanced or unbalanced?

unbalanced

500

A force of 10N to the left is exerted on a ball that is not moving. At the same time a force of 10N to the right is also exerted. What will be the result?

A. The ball will bounce up and down.

B. The ball will move to the left.

C. The ball will move to the right.

D. The ball will not move.

D.

500

Rank the following in order of greatest gravitational force to the least.

An asteroid, earth, earth's moon, the sun

The Sun, Earth, earth's moon, an asteroid.

500

The stationary part of an electric generator is the ___.

Stator

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