Answer:
Explanation:
Given that,
Initial Angular velocity w=500rpm
Converting from rpm to rad/s
1rev =2πrad
1minutes =60secs
500rpm=500rev/mins
w = 500×2π/60
wi=52.36rad/s
The final angular velocity wf=0rad/s
Time to stop is t=2.6sec
We want to find angular acceleration α
Using the equation of angular motion
wf = wi + αt.
0 = 52.36 + 2.6α
-52.36=2.6α
α = -52.36/2.6
α = -20.14rad/s²
The angular acceleration is negative because it is decelerating.
Then, α=20.14rad/s²
L = illuminance
A = surface
i = intensity
L = i / A ==: i = L * A
i = 6 lux * 4 m^2 = 24 lumen
Answer:
time taken by the wave to reach the person is 0.2 s
Explanation:
As we know that the speed of the wave is given as
here we know that the wavelength of the wave is
now speed of the wave is given as
Now time taken by the wave to reach 5 m distance is
Answer:
Explanation:
Samantha walks along a horizontal path in the direction shown the curved path is a semi circle with a radius of 2 m while the horizontal part is for me what is the magnitude of displacement
Displacement is given by the straight line distance between P and Q. Displacement will be length of straight line joining P and Q
a semi circle with a radius of 2 m
Length of this straight line=4+diameter
=4+(2*2)
=8 m
Answer: V = 15 m/s
Explanation:
As stationary speed gun emits a microwave beam at 2.10*10^10Hz. It reflects off a car and returns 1030 Hz higher. The observed frequency the car will be experiencing will be addition of the two frequency. That is,
F = 2.1 × 10^10 + 1030 = 2.100000103×10^10Hz
Using doppler effect formula
F = C/ ( C - V) × f
Where
F = observed frequency
f = source frequency
C = speed of light = 3×10^8
V = speed of the car
Substitute all the parameters into the formula
2.100000103×10^10 = 3×10^8/(3×10^8 -V) × 2.1×10^10
2.100000103×10^10/2.1×10^10 = 3×108/(3×10^8 - V)
1.000000049 = 3×10^8/(3×10^8 - V)
Cross multiply
300000014.7 - 1.000000049V = 3×10^8
Collect the like terms
1.000000049V = 14.71429
Make V the subject of formula
V = 14.71429/1.000000049
V = 14.7 m/s
The speed of the car is 15 m/s approximately.
