Its 21!! sorry i was late! :)
Answer:
radio waves, micro wave, x-rays
Explanation:
The initial velocity is 
Explanation:
The motion of the ball is a projectile motion, therefore it consists of two independent motions:
- A uniform motion (constant velocity) along the horizontal direction
- A uniformly accelerated motion, with constant acceleration (acceleration of gravity) in the downward direction
In this problem, we just need to analyze the horizontal motion: the horizontal velocity is constant, therefore the horizontal distance travelled is given by

where
is the horizontal velocity
t is the time of flight
Here we have:
t = 0.45 s
x = 3.0 m
And so solving for
, we find

And since the ball was initially projected horizontally, this is also the initial velocity.
Learn more about projectile motion:
brainly.com/question/8751410
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Answer:
The skidding distance would be doubled
Explanation:
When the truck applies the brakes and slows down, its motion is a uniformly accelerated motion, so its skidding distance can be found by using the suvat equation

where
v = 0 is the final velocity (zero since the truck comes to a stop)
u is the initial velocity
a is the acceleration
s is the skidding distance
The acceleration can also be written as

where F is the force applied by the brakes and m the mass of the truck. Substituting into the previous equation,

We see that the skidding distance is proportional to the mass: therefore, if the mass of the truck is doubled, the skidding distance will double as well.