A car accelerates from rest to a speed of 20 m/s. If its mass is 1000 kg, what i

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Question: A car accelerates from rest to a speed of 20 m/s. If its mass is 1000 kg, what is the work done on the car? (2022)

Options:

Correct Answer: 200,000 J

Exam Year: 2022

Solution:

Work Done = Change in Kinetic Energy = 1/2 * m * (v^2 - u^2) = 1/2 * 1000 kg * (20 m/s)^2 = 200,000 J

A car accelerates from rest to a speed of 20 m/s. If its mass is 1000 kg, what is the work done on the car? (2022)

A car accelerates from rest to a speed of 20 m/s. If its mass is 1000 kg, what is the work done on the car? (2022)

Step 1: Identify the initial speed (u) of the car. Since the car starts from rest, u = 0 m/s.
Step 2: Identify the final speed (v) of the car. The final speed is given as v = 20 m/s.
Step 3: Identify the mass (m) of the car. The mass is given as m = 1000 kg.
Step 4: Use the formula for kinetic energy: Kinetic Energy (KE) = 1/2 * m * v^2.
Step 5: Calculate the final kinetic energy when the car reaches 20 m/s: KE = 1/2 * 1000 kg * (20 m/s)^2.
Step 6: Calculate (20 m/s)^2, which is 400 m^2/s^2.
Step 7: Multiply 1000 kg by 400 m^2/s^2 to get 400,000 kg*m^2/s^2.
Step 8: Now multiply by 1/2: 1/2 * 400,000 = 200,000 J.
Step 9: The work done on the car is equal to the change in kinetic energy, which is 200,000 J.

Work-Energy Principle – The work done on an object is equal to the change in its kinetic energy.
Kinetic Energy Formula – Kinetic energy is calculated using the formula KE = 1/2 * m * v^2.
Units of Work – Work is measured in joules (J), which is equivalent to kg·m²/s².