The bullet falls 0.25m
The answer is -0.25m because it is falling, therefore it is negative.
Explanation:
t = dy/vy = 180m/800m/s = 0.23 secs
dy = 1/2 gt^2 = -0.25m
Answer:
Explanation:
There are 2 ways to help with this. Explain the details, which are fairly simple in this topic, or give the formula. My hope is that an explanation will last longer than memorizing the formula. I give you both.
If a wave has frequency, f, of 3 Hz, its period, T, is
1
3
s
. The wavelength,
λ
, is 5 meters. That means that in the time of one period, the wave travels 5 m.
In general,
S
p
e
e
d
=
distance
time
In applying this general definition of speed
↑
to a wave, we have
speed of the wave
=
wavelength
period
Note: we generally use v for speed of a wave. Using the variable names, then that last formula is written
v
=
λ
T
Since
T
=
1
f
, we can also say that
v
=
λ
⋅
f
So, using that last formula
v
=
5
m
⋅
3
H
z
=
15
m
s
Note: the unit Hz is equivalent to what it was called 100 years ago,
cycles
second
(
also cps
)
. Cycles is not a true unit, so the Hz contributed only the "per second" to the result
15
m
s
.
Refer to the diagrams shown below.
The normal reaction of the road on the automobile is equal to the weight of the automobile (Newtons 3rd Law).
That is,
N = mg (g = 9.8 m/s²)
When the road surface is dry, the resisting frictional force at the wheel is
F₁ = μ₁N
where
μ₁ = the kinetic coefficient of friction.
The value of μ₁ is about 0.7 - 0.9 on a dry road.
When the road is wet, the resisting frictional force is
F = μ₂N
where
μ₂ = the kinetic coefficient of friction on a wet road.
The value of μ₂ is about 0.1 - 0.4 on a wet road.
Because μ₂ < μ₁, the automobile tends to slip on a wet road, especially if the tires are worn.