What is the required power to keep a railcar moving at 40 m/s if the force applied is 1000 N?

• A. 16 kW
• B. 40 kW
• C. 600 kW
• D. 800 kW

Answer: (B)

To determine the power required to keep the railcar moving at a constant speed, we can use the formula for power, which is the product of force and velocity. In this case, the power can be calculated using the equation:

[ \text{Power} = \text{Force} \times \text{Velocity} ]

Given that the force applied to the railcar is 1000 N and the velocity is 40 m/s, the calculation would be:

[ \text{Power} = 1000 , \text{N} \times 40 , \text{m/s} = 40000 , \text{W} ]

Since 1 kW is equivalent to 1000 W, we can convert 40000 W into kilowatts:

[ 40000 , \text{W} = 40 , \text{kW} ]

Thus, the required power to maintain the railcar's speed of 40 m/s, given a force of 1000 N, is indeed 40 kW. This calculation reflects the relationship between force and velocity in achieving a specific power output in mechanical systems.