Question

4. a stone weight 2kgf is lying on the roof of a building 60 M high .calculate the amount of stored energy in the stone .(take 1 KGF is equals to 10 Newton )

5.a stone of weight 0.25 KGF is projected vertically upwards such that it attains a height of 40 M. calculate the amount of energy in the stone at the highest point (take 1 KGF is equals to 10 Newton )

6.a boy of mass 50 kg climbs stairs by spending 1200 joule of energy .how high does the boy climb up ?( take gram is equals to 10 metre per square ​

Answer 1

Answer:

4. 1200 Joule

5. 100 Joule

6. 2.5 metre

Explanation:

4. The energy stored in the stone will be the potential energy

mass of the stone m = 2kg

Height h = 60 m

The potential energy of the stone

$PE=mgh$

$\implies PE=2\times 10\times 60$

$\implies PE=1200$ Joule

5. The stone is projected with some velocity at the highest point its velocity will be zero and its all kinetic energy will have converted into potential energy

Mass of the stone m = 0.25 kg

Height attained by the stone h = 40 m

The energy stored in the stone = Potential energy of the stone

$PE=mgh$

$\implies PE=0.25\times 10\times 40$

$\implies PE=100$ Joule

6. When the boy spends 1200 Joules of energy, it will reach a height where his Potential energy is 1200 J

Mass of the boy m = 50 kg

Let the height be h

Potential energy of the boy PE = 1200 J

Using

$PE=mgh$

we get

$h=\frac{PE}{mg}$

$\implies h=\frac{1200}{50\times 10}$

$\implies h=2.4$ m

Hope this helps.

Answer 2

Answer:

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