A car of mass 1000 kg accelerates from rest to a speed of 20 m/s. What is the wo
Practice Questions
Q1
A car of mass 1000 kg accelerates from rest to a speed of 20 m/s. What is the work done on the car?
20000 J
40000 J
80000 J
100000 J
Questions & Step-by-Step Solutions
A car of mass 1000 kg accelerates from rest to a speed of 20 m/s. What is the work done on the car?
Correct Answer: 200000 J
Step 1: Identify the mass of the car, which is 1000 kg.
Step 2: Identify the final speed of the car, which is 20 m/s.
Step 3: Use the formula for kinetic energy, which is KE = 0.5 × m × v^2.
Step 4: Substitute the mass (1000 kg) into the formula.
Step 5: Substitute the speed (20 m/s) into the formula.
Step 6: Calculate (20 m/s)^2, which is 400 m^2/s^2.
Step 7: Multiply 0.5 by 1000 kg, which gives 500 kg.
Step 8: Multiply 500 kg by 400 m^2/s^2, which gives 200000 J.
Step 9: Conclude that the work done on the car is 200000 J.
Kinetic Energy – The work done on an object is equal to the change in its kinetic energy, which can be calculated using the formula KE = 0.5 × m × v^2.
Work-Energy Principle – The work done on an object is equal to the change in its kinetic energy, emphasizing the relationship between work and energy.
