Potential energy class 9th (lec 3)

 video lectures for potential energy 

Question 1: Define and derive an expression for gravitational potential energy.

Question 2: Stretched spring has the energy in the form of potential energy.

Question 3: Work and energy have the same `S.I.` units.

Question 4: When a spring having spring constant `2 Nm^{-1}` is

stretched by `5 cm`, the energy stored in it is

(a) `0.025 J`  

(b) `0.0025 J`

(c) `0.25 J`  

(d) `2.5 J`

Question 5: What is the energy of a stone weighing `10 g` placed at a height of `5` meters?

(`g=9.8 ms^{-2}`)

a) `9.8 J`

b) `0.49 J`

c) `5 J`

d) `8.9 J`

Answer key

Q1  `E_{p}=mgh`

Q2  True,   Q3 True

Q4  (b) ,   Q5  (b)