Forces car of mass question

In summary, the question is about calculating the power of an engine for a car with a mass of 1500kg moving at a max speed of 144km/h up an incline of 1 in 49 against a frictional resistance of 500N. The conversation also mentions neglecting other factors that affect auto efficiency and suggests looking at displacement to compute the work done by the engine.
  • #1
i have this question for an engineering science assignment, and can't remember how to work it out, any help would be greatly appreciated.

A car of mass 1500kg has a max speed of 144km/h up an incline of 1 in 49 against a frictional resistance of 500N. Calculate the power of the engine.
Physics news on
  • #2
Neglecting the usual frictional losses in the engine and drivetrain, air resistance, etc, which reduce auto efficiency to about 25%, it would seem at a steady state where acceleration=0, whatever force being generated is just equal to the opposing gravitational force and frictional force. I would think then that you need to look at the displacement, both vertical and against friction to compute the work done by the engine. Hope that's a help as one is supposed to show work prior to any major assistance being given.
  • #3

I would recommend approaching this question by first understanding the concept of power and how it relates to the given scenario. Power is the rate at which work is done or energy is transferred. In this case, the car's engine is doing work by overcoming the resistance of friction to move the car up the incline.

To calculate the power of the engine, we can use the formula P = F x v, where P is power, F is force, and v is velocity. In this scenario, the force we are interested in is the net force, which is the force produced by the engine minus the force of friction. We can calculate the net force by using the formula Fnet = ma, where m is the mass of the car and a is the acceleration.

To find the acceleration, we can use the formula a = (v^2 - u^2)/2s, where v is the final velocity, u is the initial velocity (in this case, 0), and s is the distance traveled up the incline. Plugging in the given values, we get a = (40^2 - 0^2)/2(49) = 0.816 m/s^2.

Now, we can calculate the net force by using Fnet = ma = (1500kg)(0.816 m/s^2) = 1224 N. To find the engine's power, we can plug in this value for force and the given velocity of 40 m/s into the formula P = F x v. This gives us P = (1224 N)(40 m/s) = 48,960 watts or 48.96 kW.

In conclusion, the power of the engine in this scenario is 48.96 kW. It is important to understand and apply the relevant formulas and concepts to solve engineering science problems like this. I hope this explanation helps and good luck with your assignment!

What is a "Forces car of mass"?

A "Forces car of mass" refers to a car or vehicle that is being affected by various forces such as gravity, friction, and air resistance, and has a specific mass that contributes to its overall motion and acceleration.

How is the mass of a car related to its forces?

The mass of a car directly affects the forces acting upon it. Heavier cars have more mass and therefore require more force to accelerate or decelerate. This is why larger vehicles like trucks or buses require more time and distance to change their speed compared to smaller cars.

What is the role of forces in a car's motion?

Forces play a crucial role in a car's motion. The engine of a car produces a force that pushes it forward, while other forces such as friction and air resistance act in the opposite direction, slowing the car down. The balance between these forces determines the car's speed and acceleration.

How does mass affect a car's ability to stop?

The mass of a car affects its ability to stop because it directly impacts the amount of force needed to slow it down. A heavier car has more momentum and requires more force to stop, while a lighter car can be stopped with less force. This is why it is important for cars to have properly functioning brakes and for drivers to maintain a safe distance from other vehicles.

Can the mass of a car change?

The mass of a car can change if any additional weight is added or removed. For example, if a car is loaded with heavy cargo, its mass will increase, and therefore, more force will be needed to accelerate or stop it. Similarly, if the cargo is removed and the car becomes lighter, it will require less force to move. However, the mass of a car itself does not change unless its materials are physically altered.

Suggested for: Forces car of mass question