Answer:
When air resistance equals the weight of an object, the object has reached free fall.
Explanation:
- When an object has only force acting on it as gravity then, it experiences free fall.
- During free fall all the forces except gravity is balanced by one another.
- In the question, object's weight is balanced by air resistance so it is in the state of free fall.
- At the null point of free fall, object experiences weightlessness i.e. it feels like object is not attracted by any force.
Answer:
d. 50 C
Explanation:
In this problem, we have to add 800 ml of water at 20 Celsius to 800 ml of water at 80 Celsius.
According to the 2nd law of thermodynamics, heat transfers from hot to cold temperature.
The quantity of both the different waters is equal so this makes it very easy. All we have to do is find the mean of both the temperatures:
Final temperature = (20 C + 80 C)/2
= 50 Celsius
Answer: liquid
explanation: 1 liter is a measurement of liquids, not solids, or gases.
Liquids also have a set volume, but can flow to take the shape of the bottom of their container.
Answer:
c. A, C
Explanation:
On equi-potential surface, fields are equal in magnitude at all points . If field is zero at all points , they will be equal so first option is correct.
Field is perpendicular to equipotential surface at all points.