Question

A 2.0 kg object is moving along a straight line with a speed of 4.0 m/s. In order to increase its speed to 8.0 m/s. the net work done on the object must be:
Options :
1. 24J
2. 36 J
3. 48 J
4. 60 J
​

Answer 1

Given :-

▪ Mass of object = 2kg

▪ Initial velocity = 4mps

▪ Final velocity = 8mps

To Find :-

▪ Net work done to increase the speed of object.

Concept :-

This question is completely based on concept of 'Work-Energy theorem'.

As per Work-Energy theorem, work done is always equal to the change in energy.

Mathematically,

$\bigstar\:\underline{\boxed{\bf{\pink{Work=\triangle{Energy}}}}}$

Calculation :-

$\implies\sf\:W=\triangle{KE}\\ \\ \implies\sf\:W=(KE)_2-(KE)_1\\ \\ \implies\sf\:W=\dfrac{1}{2}m({V_2}^2-{V_1}^2)\\ \\ \implies\sf\:W=\dfrac{1}{2}\times 2(8^2-4^2)\\ \\ \implies\sf\:W=(64-16)\\ \\ \implies\boxed{\bf{\purple{W=48\:J}}}$

Answer 2

Answer:

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