27. 20,000 hertz
28. A stream of photons
29. Either infrared or gamma
Answer:
Explanation:
Given that,
Initial velocity, u = 10 m/s
Final velocity, v = 0 (stops)
Time, t = 30 s
We need to find the acceleration of the lion.
We know that,
Acceleration = rate of change of velocity
So, the acceleration of the lion is 
.
Answer: That's air resistance.
Explanation: Well, air resistance is an upward force exerted on falling objects.
( I hope this helped <3 )
That depends on the wavelength of the electromagnetic radiation.
-- If the waves are long, then we use them for radio, TV, and cellphones.
-- If the waves are shorter than that, then we use them for GPS in the car.
-- If the waves are shorter than that, then we use them to heat meatloaf
in the microwave oven.
-- If the waves are shorter than that, then they warm us and they
make our plants grow ... like the ones we eat.
-- If the waves are shorter than that, then our eyes use them to see with.
-- If the waves are shorter than that, then they tan our skin.
-- If the waves are shorter than that, then they can cause cancer on
our skin.
-- If the waves are shorter than that, then they can cause cancer and
other diseases in places inside our body.
When all parts of a circuit are composed of conducting materials,
then it's possible for current to flow in the circuit, and we say that
the circuit is "closed".
