Answer:
The answer to your question is: t = 2.5 s
Explanation:
Data
vo = 30 m/s
a = -12 m/s2
t = ?
vf = 0 m/s
Formula
vf = vo + at
Substitution
0 m/s = 30 + (-12)t
Solve it for t -30 = -12t
t = -30 / -12
t = 30/12 = 15/6 = 5/2
t = 2.5 s
Cheese I'm so sorry for not having an answer I failed you
To claculate the gravitational attraction between two bodies with mass 1(m1) and mass 2 (m2) you need to use the equation:
F= G ((m1*m2)/r^2)
Where;
G is the gravitational constant (6.67E-11 m^3 s-2 Kg-1) and
r is the distance between the two objects.
Answer:
Speed of physicist car is 0.036c or 1.08 x 10⁷ m/s .
Explanation:
Doppler Effect is defined as the change in frequency or wavelength of the wave as the source or/and observer moving away or towards each other.
In this case, the Doppler effect equation in terms of wavelength is :
......(1)
Here 
is source wavelength, 
is observed wavelength, v is speed of the observer and c is the speed of light.
Given :
Source wavelength, = 660 nm = 660 x 10⁻⁹ m
Observed wavelength, 
= 555 nm = 555 x 10⁻⁹ m
Substitute these values in the equation (1).
v = 1.08 x 10⁷ m/s
Since the ladder is standing, we know that the coefficient
of friction is at least something. This [gotta be at least this] friction
coefficient can be calculated. As the man begins to climb the ladder, the
friction can even be less than the free-standing friction coefficient. However,
as the man climbs the ladder, more and more friction is required. Since he
eventually slips, we know that friction is less than what's required at the top
of the ladder.
The only "answer" to this problem is putting lower
and upper bounds on the coefficient. For the lower one, find how much friction
the ladder needs to stand by itself. For the most that friction could be, find
what friction is when the man reaches the top of the ladder.
Ff = uN1
Fx = 0 = Ff + N2
Fy = 0 = N1 – 400 – 864
N1 = 1264 N
Torque balance
T = 0 = N2(12)sin(60) – 400(6)cos(60) – 864(7.8)cos(60)
N2 = 439 N
Ff = 439= u N1
U = 440 / 1264 = 0.3481
