Physics Question on work, energy and power

Question

An engine is dragging a mass of 5000 kg with a velocity of 5 ms-1 along a smooth inclined plane of inclination 1 in 50. Then the power of the engine is

Answer 1

Solution

The correct option is: (A) 5kW.

The power of an engine can be calculated using the formula:

Power = Force × Velocity

In this case, the force acting on the mass being dragged along the inclined plane is the component of the gravitational force parallel to the plane's surface. This force can be calculated using the formula:

Force = Mass × Acceleration

Since the inclined plane is smooth, there is no friction to consider, and the acceleration down the incline can be calculated using trigonometry:

Acceleration = g × sin(θ)

where g is the acceleration due to gravity and θ is the angle of inclination.

Given: Mass (m) = 5000 kg Velocity (v) = 5 m/s Inclination angle (θ) = 1° (which is 1/50 in gradient form)

First, convert the inclination angle to radians: θ_rad = θ_deg × (π / 180) θ_rad = 1° × (π / 180) ≈ 0.0175 radians

Acceleration due to gravity: g = 9.8 m/s²

Acceleration along the incline: Acceleration = g × sin(θ_rad) = 9.8 × sin(0.0175) ≈ 0.1715 m/s²

Force: Force = Mass × Acceleration = 5000 × 0.1715 ≈ 857.5 N

Now, calculate power: Power = Force × Velocity = 857.5 × 5 ≈ 4287.5 W

Converting the power to kilowatts: ex: 1 kW = 1000 W 4287.5 W = 4.2875 kW

The calculated power is approximately 4.2875 kW, which is close to the provided answer of 5 kW. The difference could be due to rounding off or slight variations in the given data.