Question

A force of 20 N continuously acts on a body. The body has a speed of 5 m/s at certain
instant. Find the power at that instant.​

Answer 1

GIVEN:

★A force if 20N acts continuously on a body.

★Velocity at that instance is 5m/s.(v)

TO FIND:

★Power at that instance.

CONCEPT USED:

★We would deriving a relationship between power, force and velocity.

ANSWER:

Firstly we know,

Rate of doing work is called power.

So,

$\large\green{\boxed{P=\dfrac{W}{t}}}$

where P is power, W is work done and t is the time taken.

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Taking this relationship,

=>$P =\dfrac{W}{t}$

=>$P =\dfrac{F.s}{t}$

where F is the force and s is displacement.

=>$P = F(\dfrac{s}{t})$

=>$P =Fv$

$\large\red{\boxed{v =\dfrac{s}{t}}}$

Hence power = F× v.

$\large\purple{\boxed{P =Fv}}$

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Using this

=>$P =Fv$

=>$P = 20N\times5m/s$

. °. $P =100Watt$

Hence the required power is 100W.

$\huge\orange{\boxed{.°.P =100W}}$