If a 3 kg object is moving with a speed of 4 m/s and comes to a stop, what is th

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Question: If a 3 kg object is moving with a speed of 4 m/s and comes to a stop, what is the work done by the friction?

Options:

Correct Answer: -48 J

Solution:

Initial kinetic energy = 0.5 × 3 kg × (4 m/s)² = 24 J. Work done by friction = -24 J.

If a 3 kg object is moving with a speed of 4 m/s and comes to a stop, what is the work done by the friction?

If a 3 kg object is moving with a speed of 4 m/s and comes to a stop, what is the work done by the friction?

Step 1: Identify the mass of the object, which is 3 kg.
Step 2: Identify the speed of the object, which is 4 m/s.
Step 3: Use the formula for kinetic energy: KE = 0.5 × mass × speed².
Step 4: Plug in the values: KE = 0.5 × 3 kg × (4 m/s)².
Step 5: Calculate (4 m/s)², which is 16 m²/s².
Step 6: Multiply 0.5 × 3 kg × 16 m²/s² to get 24 J.
Step 7: The initial kinetic energy of the object is 24 J.
Step 8: When the object comes to a stop, all of this energy is used to overcome friction.
Step 9: The work done by friction is equal to the negative of the initial kinetic energy, which is -24 J.

Kinetic Energy – The energy an object possesses due to its motion, calculated as 0.5 × mass × velocity².
Work-Energy Principle – The work done on an object is equal to the change in its kinetic energy.
Friction – A force that opposes the motion of an object, doing negative work when it stops the object.