Rankers Physics

Work Energy Theorem: Practice Problem & Solution

A bullet having mass 10 g is fired towards a fixed wooden block with velocity of 30 m/s. If it comes out of the block with velocity of 20 m/s, then the total work done by the resistive forces is
+ 4.5 J
- 4.5 J
+2.5 J
- 2.5 J

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Work Energy Theorem. Understanding the underlying formula is key to arriving at the correct answer below:

By Work Energy Theorem, 

Work Done= Change in Kinetic Energy

⇒W= ½×(10/ 1000) × ( 20²- 30²) = -500/200= - 2.5 J

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