Vf = final velocity
vo = initial velocity
a = acceleration
t = time
use the following equation
vf = vo + at
since vo = 0 m/s (stopped), that term drops out and you're left with . . .
vf = at
(60 m/s) = (8.0 m/s²)t
t = (60 m/s)/(8.0 m/s²) = 7.5 seconds
<u><em>t = 7.5 seconds</em></u>
Assume it is in uniform deceleration.
u=25
v=0
s=x
a=?
t=12
v=u+at
0=25+a(12)
a=-2.08(3sig fig)
decelerarion of 2.08 ms^(-2)/
acceleration=-2.08ms^(-2)
Answer:
194 V/m
Explanation:
In order to find electric field, we can use the formula of power density
i.e Pd = E^2 / Z
where:
Pd = power density in W/m^2
E = electric field strength in V/m
Z = impedance of free space = 120 * π
E = sqrt(Pd * Z)
-----> re-arranging it for E
before solving, convert Pd unit into W/m^2
Pd= 5mW/cm^2 = 50 W/m^2
Solving for E:
E= sqrt(50 * 120 * π)
E = 137.3 V/m
the above value is RMS value
In order to find the peak amplitude of the oscillating field will therefore be 137.3 * sqrt(2) = 194 V/m
Answer:
238.75⁰C .
Explanation:
coefficient of linear thermal expansion of aluminum and steel is 23 x 10⁻⁶ K⁻¹ and 12 x 10⁻⁶ K⁻¹ respectively .
Rise in temperature be Δ t .
Formula for linear expansion due to heat is as follows
l = l₀ ( 1 + α x Δt )
l is expanded length , l₀ is initial length , α is coefficient of linear expansion and Δt is increase in temperature .
For aluminum
l = 2.5 ( 1 + 23 x 10⁻⁶ Δt )
For steel
l = 2.506 ( 1 + 12 x 10⁻⁶ Δt )
Given ,
2.5 ( 1 + 23 x 10⁻⁶ Δt ) = 2.506 ( 1 + 12 x 10⁻⁶ Δt )
1 + 23 x 10⁻⁶ Δt = 1.0024 ( 1 + 12 x 10⁻⁶ Δt )
1 + 23 x 10⁻⁶ Δt = 1.0024 + 12.0288 x 10⁻⁶ Δt
10.9712 x 10⁻⁶ Δt = .0024
Δt = 218.75
Initial temperature = 20⁰C
final temperature = 218.75 + 20 = 238.75⁰C .
