Question

work
Power depends on
the time in which
energy is spent.
3. S.I. unit of power is
watt (W).
moves a body through
m in the direction of
the work done by the
= 10 kg
= 100 NX 8 m
= 800 J
5. A body of mass 5 kg is taken from a
height of 3 m to 6 m. Find the increase
in the potential energy of the body.
Take g = 10 N kg.
Solution : Given, m = 5 kg, h, = 3 m, h = 6 m,
g = 10 N kg
Increase in potential energy
= mgh, - mgh
= mg (
hh)
= 5 x 10 x (6-3) J
= 200 N, d = 2 m
= 150 J
a
culls from
Smt. RAMDEVI SOBHRAJ BAJAJ ARYA VIDYA MANDIR JUHU
Std 8
Numericals
Physics
Force and pressure
Q.2 The moment of a force of 25 N about a point is 2.5 N m. Find the perpendicular distance of
force from that point
nit hinnhan-minimum​

Answer 1

${\bf{Given\::}}$

Mass of a body is 5 kg.

The body is taken from a height of 3 m to 6 m.

Gravitational acceleration (g) = 10 m/s²

$\\ {\bf{To\: Find\::}}$

The increase in potential energy of the body.

$\\ {\bf{Solution\::}}$

As we know that,

☛ Potential energy of a body is given as,

$\orange\bigstar\:{\Large\mid}\:\bf\blue{P.E\:=\:m\:g\:h\:}\:{\Large\mid}\:\green\bigstar$

☛ And increase in potential energy of a body (which denotes the height factor) is given as

$\red\checkmark\:\bf{P.E\:=\:m\:g\:(h_2\:-\:h_1)\:}$

Where,

h₁ = 3 m

h₂ = 6 m

➠ P.E = 5 × 10 × (6 - 3)

➠ P.E = 5 × 10 × 3

➠ P.E = 150 Joules

∴ The increase in potential energy of the body is 150 J.