A 3 kg object is moving with a velocity of 4 m/s. If it comes to a stop, what is

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Question: A 3 kg object is moving with a velocity of 4 m/s. If it comes to a stop, what is the work done by the friction force?

Options:

Correct Answer: -48 J

Solution:

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

A 3 kg object is moving with a velocity of 4 m/s. If it comes to a stop, what is the work done by the friction force?

A 3 kg object is moving with a velocity of 4 m/s. If it comes to a stop, what is the work done by the friction force?

Step 1: Identify the mass of the object, which is 3 kg.
Step 2: Identify the initial velocity of the object, which is 4 m/s.
Step 3: Calculate the kinetic energy of the object using the formula: Kinetic Energy = 0.5 × mass × (velocity)².
Step 4: Plug in the values: Kinetic Energy = 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: Since the object comes to a stop, the work done by the friction force is equal to the negative of the kinetic energy.
Step 8: Therefore, Work done by friction = -24 J.

Work-Energy Principle – The work done by the friction force is equal to the change in kinetic energy of the object.
Kinetic Energy Calculation – Kinetic energy is calculated using the formula KE = 0.5 × mass × velocity².
Sign of Work Done – Work done by friction is negative because it acts in the opposite direction to the motion.