Question

12. 8000 J of work is done by a machine to lift a mass
of 100 kg vertically upwards. Calculate the height to
which the mass is lifted. (take g = 10 m/s2)
[Ans. 8 m]​

Answer 1

Given :-

• work done, w = 8000 J
• mass, m = 100 kg
• acceleration, g = 10 m/s²

To Find :-

• height which the mass is lifted or displacement ?

Solution :-

we know that,

$\underline {\boxed{ \bold{work = force \times displacement}}}$

and

$\boxed{ \bold{force = mass \times acceleration}}$

$\bold{: \implies 100 \times 10} \\ \\ \bold{: \implies 1000 \: N} \: \:$

• so, force = 1000 N

now,

and we have

• work = 8000 J

$\bold{: \implies 8000 = 1000 \times height} \\ \\ \bold{: \implies height = \cancel \frac{8000}{1000} } \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ \\ \bold{: \implies height = 8 \: m \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: }$

hence, the height on which the mass is lifted is 8 m