Radar

guns

Radar

guns

are

used

by

police

to

measure

the

speed

of

cars.

The

radar

gun

gives

out

radio

waves

that

bounce

off

the

moving

car.

The

length

of

these

waves

changes

as

the

car

moves

past.

The

gun

measures

the

waves

and

determines

the

speed

of

the

car.

Radar

guns

are

also

used

to

measure

the

speed

of

balls

in

sports

such

as

tennis,

hockey,

baseball

and

soccer.