Question

cyclist brakes, his kenetic energy stops
and recduced from 1400J to zero in a distance
of 7m. Calculate the braking force.​

Answer 1

Given :

Initial kinetic energy = 1400 J

Final kinetic energy = zero

Distance travelled = 7 m

To Find :

Breaking force or better to say retarding force.

Solution :

❒ Body was moving with some velocity then velocity decreased due to applying brakes. Finally body came to rest after traveling some distance.

This question can be solved by applying concept of work energy theorem.

As per WET, W = ∆K

» W denotes work

» ∆K denotes change in KE

We know that work done is defined as the product of force and displacement$.$

So final equation will be,

➠ F d = K (final) - K (Initial)

By substituting the given values;

➠ F × 7 = (0 - 1400)

➠ F = -1400/7

➠ F = -200N

[Negative sign shows that force acts in opposite direction or it is a retarding force.]

Answer 2

$\begin{lgathered}\begin{lgathered}\begin{lgathered}\bf {\pink{Given}}\begin{cases} \sf{\green{Initial~ Kinatic~ Energy = 1400J}}\\ \sf{\blue{Final~ Kinatic~ Energy = 0}}\\ \sf{\orange{Distance~ traveled = 7 m}}\end{cases}\end{lgathered} \:\end{lgathered}\end{lgathered}$

⠀

To find:-

• Braking force.

⠀

Solution:-

★ Using Equation:-

$\star{\large{\boxed{\sf{\orange{F~ d = k - k}}}}}$

⠀

$\large{\tt{\longmapsto{F \times 7 = 0 - 1400}}}$

⠀

$\large{\tt{\longmapsto{F = \dfrac{-1400}{7}}}}$

⠀

$\large{\tt{\longmapsto{F = -200 N}}}$

⠀

Hence, the Braking force is -200 N.

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