(a). The power of the candy bar is,

The time taken to play on 800 kJ energy of the candy bar is,

where E is the energy.
Substituting the known values,

As 1 minute is equal to 60 seconds,
Thus,

Thus, the time taken to play tennis on the 800 kJ energy is 30.3 minutes.
(b). By doing the exercise, the process of digestion of food inside our body increases. Thus, the exercise does not helps us to burn the calories. But it helps us to diggest the heavy meal like candy bar easily.
The time taken to digest the canndy bar or to utilise its energy is large because it takes a lot of time to burn small amount of food and make it digest quickly.
Answer:
3.45×10⁻⁴mm (or 0.000345mm)
Explanation:
Use a method called dimensional analysis here. It involves a chain of conversions, so we'll need some conversions to work with.
- 1nm = 1×10⁻⁹m
- 1mm = 1×10⁻³m
- 345nm; which is given
If you knew the conversion from nanometers to millimeters then you could just do it in one step. But I don't, so I won't. Anyways, you put the conversions into fraction form like so:
And then orient them in a way where multiplying the two (or more in other instances) gives you the units you want. In this cas it's millimeters so you'll have:
(345nm)•(1×10⁻⁹m/1nm)•(1mm/1×10⁻³m)
Notice how all the units reduce except for mm. From here you just multiply across and should get 345×10⁻⁶mm which simplifies to 3.45×10⁻⁴mm.
1. Communication
In early ages people were using letters to communicate between them. Now days instantly we can call one person from anywhere, these are based on optical fiber communication and it is an application of physics.
2. Transportation
We can travel from place to anther place by aeroplane , these technologies are introduced after advancement in physics.
3. Construction
Earlier people used to stay in small houses, now days apartments with many number of storeys are built by considering all the forces coming on the structure.
4. Medical Department
The invention of many equipment increased the health of humans.
5. Weather forecasting
The prediction of weather considering all the available factors, prediction of natural disasters all are application of physics.