Answer:
5.73kg
Explanation:
Given data
Height = 8m
Potential Energy = 450J
Required
The mass of the object
From the following expression
PE=mgh
we can substitute g= 9.81m/s^2 and the other parameters to get mass m
450= m*9.81*8
450= m* 78.48
m= 450/78.48
m= 5.73kg
Hence the mass is 5.73kg
It is true that the light is 15.000 more dangerous than the radiation of a microwave.
<h3>What is the wavelength?</h3>
The wavelength shows the extent or how far the wave travels. Now we know that the energy of the wave can be use to find out how much dangerous the wave is.
Now;
1.6 * 10^-19 J = 1eV
x J = 1.8 eV
x = 1.8 eV * 1.6 * 10^-19 J /1eV
x = 2.88 * 10^-19 J
Now if the energy of the microwaves is 1.2 x 10^-4 J, then it follows that;
2.88 * 10^-19 J/ 1.2 x 10^-4 J,
= 2.4 * 10^15
Hence, it is true that the light is 15.000 more dangerous than the radiation of a microwave.
Learn more about microwave:brainly.com/question/15708046
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Answer:
Volume of balloon = 1000 cm^3
Explanation:
The head of a normal person can be assumed as a sphere with radius 10 cm.
Volume of sphere 
, where r is the radius.
We have approximate radius = 10 cm.
Approximate volume of head 
In the given options the closest value to the approximate volume is 1000 cm^3.
So, volume of head = Volume of balloon = 1000 cm^3
Answer:
3.32 m/s
Explanation:
From the law of conservation of energy, the sum of mechanical and kinetic energy should be equal to the 10 J given. Potential energy is given by mgh where m is mass, g is acceleration due to gravity and h is the height. For this case, 
and l is string length, given as 2 m, \theta is given as 50 degrees. Kinetic energy is given by 
and it is this velocity that is unknown.
