Question

If the work done by a motor to lift a 200 kg block
to a heighth is 30 kJ, then calculate the value of
height (h) in metres (Take, g= 10 m/s2).​

Answer 1

Given :

Mass of block = 200kg

Work done = 30kJ

To Find :

The value of height in meters.

Solution :

■ Work is measured as the product of force and displacement.

• It is a scalar quantity having only magnitude.
• It can't be negative or zero.
• SI unit : J or N m

Mathematically, $\underline{\boxed{\tt{\orange{W=F\:d}}}}$

In this case, only gravitational force is acting on the block which is equal to mg.

where,

g denotes gravitational acceleration

$:\implies\tt\:W=F\:d$

• Taking d = H & F = mg

$:\implies\tt\:W=(mg)\:H$

$:\implies\tt\:30\times 1000=200\times 10\times H$

$:\implies\tt\:H=\dfrac{30,000}{2,000}$

$:\implies\tt\:H=\dfrac{30}{2}$

$:\implies\:\underline{\boxed{\bf{\purple{H=15\:m}}}}$

Answer 2

Answer:

Given :

Mass of block = 200kg

Work done = 30kJ

To Find :

The value of height in meters.

Solution :

■ Work is measured as the product of force and displacement.

It is a scalar quantity having only magnitude.

It can't be negative or zero.

SI unit : J or N m

Mathematically, \underline{\boxed{\tt{\orange{W=F\:d}}}}

W=Fd

In this case, only gravitational force is acting on the block which is equal to mg.

where,

g denotes gravitational acceleration

:\implies\tt\:W=F\:d:⟹W=Fd

Taking d = H & F = mg

:\implies\tt\:W=(mg)\:H:⟹W=(mg)H

:\implies\tt\:30\times 1000=200\times 10\times H:⟹30×1000=200×10×H

:\implies\tt\:H=\dfrac{30,000}{2,000}:⟹H=

2,000

30,000

:\implies\tt\:H=\dfrac{30}{2}:⟹H=

2

30

:\implies\:\underline{\boxed{\bf{\purple{H=15\:m}}}}:⟹

H=15m