Answer:
a)mass = 300kg
b) no of atoms = 1.81 x 10^26atoms.
c)Fission Activity = 207Bq
d) no of fissions = 1.79 × 107 d^-1
Explanation:
a)mass= (3×10-4)(10^6kg) = 300kg
b) no of atoms = (300kg) X (6.022×10^23/kg) = 1.81 x 10^26atoms.
c)Fission Activity = (0.69)(300kg) = 207Bq
d) no of fissions = (207)(86400) = 1.79 × 107 d^-1
As per Newton's law of cooling we know that

in 5 hours the body temperature becomes 79.6 from 84.4
while the surrounding temperature is given as 68 degree F
now from above formula


now let say the person died "t" time ago
now we will have




so he died at approx 5 Am in morning
Answer:
Power will be 0.2023 watt
And when amplitude is halved then power will be 0.0505 watt
Explanation:
We have given mass of the Piano wire m = 2.60 gram = 0.0026 kg
Length of wire l = 84 cm = 0.84 m
So mass density 
Tension in the wire T = 25 N
Frequency f = 120 Hz
So angular frequency 
And amplitude A = 1.6 mm = 0.0016 m
We have to find the generated power
Power is given by 
From the relation we can see that power 
So if amplitude is halved then power will be
times
So power will be equal to 
Basically velocity is a vector quantity and is specified in m/s (meters/second). Speed is the distance traveled by an object where as, velocity is distance traveled by an object per unit time in a particular direction. Speed is a scalar quantity where as velocity is a vector quantity