Force of gravity on an object is the weight of the object and is given by mass times accerelation due to gravity. The accerelation due to gravity is the accerelation of an object in free fall and is given by 9.8m/s^2. Given that the force of gravity acting on a child's mass on earth is 490 newtns, i.e. F = mg which means that 490 newtons = 9.8 times mass. Therefore, mass of the child is 490 / 9.8 = 50 kg.
Answer:
Independent variable
Explanation:
The temperature of air inside the box depends on the time that the booxes sat on the window sill.
Answer:

Explanation:
Let consider that the person hit the ground in the negative direction. The physical model for the impact is modelled after the Impact Theorem:

The impact is:



The force of impact is derived as follows:



Answer:
Q = 640425 J = 640.425 KJ
Explanation:
From the law of conservation of energy:
Heat Addition = Heat Gain of Water + Heat Gain of Aluminum Kettle

where,
Q = Heat addition required = ?
= mass of water =1.8 kg
= mass of aluminum kettle = 1.1 kg
= specific heat capacity of water = = 4200 J/kg.°C
= specific heat capacity of aluminum kettle = = 890 J/kg.°C
=
= change in temperature of water and kettle = 95°C - 20°C = 75°C
Therefore,

Q = 567000 J + 73425 J
<u>Q = 640425 J = 640.425 KJ</u>