Question

A block of mass 50 kg starts from rest a force of 10 N Act for 10 sec find the kinetic energy

Answer 1

Answer:

Kinetic energy : 100 J

Explanation:

Given,

Mass of the block is 50 kg.

Force reactivity for the given time is 10N.

Time : 10 seconds.

Since the block starts moving from rest, initial velocity of the block must be 0.

= > F( or force ) = m( mass ) x a( acceleration ) { F = m.a }

Let v be the final velocity of the block and u ( here, 0 ) be the initial velocity of the block.

= > 10N = 50 Kg x ( v - u ) / t { Acceleration = change in velocity / change in time }

= > 10 = 50 x ( v - 0 ) / 10 ( s / m )

= > 100 / 50 = v ( s / m )

= > 2 m / s = v( or final velocity )

We know,

• Kinetic energy = 1 / 2 mv^2

Here,

= > Kinetic energy = 1 / 2 x ( 50 x 2 x 2 ) J

= > Kinetic energy = 100 J

Answer 2

Answer:

$\large\bold\red{K.E=100\;Joule}$

Explanation:

So,

What's the given quantities here ?

A block having,

• Mass , m = 50 Kg
• Force, f = 10 N
• Time, t = 10 sec

To find,

• Kinetic Energy , KE = ?

We know that,

• $\large \boxed{ \purple{K.E = \frac{1}{2} m {v}^{2} }}$
• Where, v is velocity.

Now,

We know that,

• v = at
• where, a is acceleration.

So,

Substituting the values,

We get,

• $\large \boxed{ \purple{K.E = \frac{1}{2} m {a}^{2} {t}^{2} }}$

Now,

We know that,

• $a = \frac{f}{m}$

Therefore,

Substituting the values,

We get,

• $\large \boxed{ \purple{K.E = \frac{1}{2} \frac{ {f}^{2} {t}^{2} }{m} }}$

Substituting the given values,

We get,

$= > K.E = \frac{1}{2} \times \frac{ {(10)}^{2} {(10)}^{2} }{50} \\ \\ = > K.E = \frac{ {10}^{4} }{ {10}^{2} } \\ \\ = > K.E = 100$

Hence,

Kinetic Energy = 100 Joule