(900 kg)(9.81 m/s2) is the forge due to gravity. It acts in a direction perpendicular to the displacement of the car, so that force does zero work.Nanu Nana said:Homework Statement
A car (mass 900 kg) runs 12 km along a level road at a constant speed of 80 km / h. The friction force is 500N. Calculate the work done by the engine
Homework Equations
W= F x displacement[/B]The Attempt at a Solution
W= (900x 9.81) N x 12000m
W=10594800 J
But this is wrong .answer should be 6 x10^6 J
Correct !Nanu Nana said:oh friction force
so
Work = Friction force x (12000m)
W= 500 N x 12000m
W=6 x10^6 Joule
Thank you very much . Where on forum should i ask if i want explanation about vectors components?SammyS said:Correct !
Nanu Nana said:Thank you very much . Where on forum should i ask if i want explanation about vectors components?
Nanu Nana said:Thank you very much . Where on forum should i ask if i want explanation about vectors components?
If it's a from a homework problem or closely related to one, then this is the correct forum.Nanu Nana said:Thank you very much . Where on forum should i ask if i want explanation about vectors components?
Calling the resistance to a car's normal motion simply 'friction' is one of my pet hates. It's so confusing for students. What the question means is some combination internal friction (bearings etc.), rolling resistance and drag. The friction between the tyres and the road is precisely what allows the car to get anywhere. In the context of the problem, it would be acting in the forward direction.Nanu Nana said:A car (mass 900 kg) runs 12 km along a level road at a constant speed of 80 km / h. The friction force is 500N. Calculate the work done by the engine
Work done by a car engine refers to the amount of energy expended by the engine to produce motion or force. This can be measured in units of joules (J) or newton-meters (Nm).
The formula for calculating work done by a car engine is W = F x d, where W is work (in J or Nm), F is the force applied (in newtons), and d is the distance over which the force is applied (in meters). It can also be calculated by multiplying the engine's torque (in Nm) by the number of revolutions per minute (rpm) and dividing by 60.
The work done by a car engine can be affected by various factors such as the engine's power, efficiency, and operating conditions (e.g. speed, load, temperature). The type of fuel and maintenance of the engine can also impact the work done.
Calculating work done by a car engine can help determine its performance and efficiency. This information can be used to make improvements and optimize the engine's operation, leading to better fuel economy, reduced emissions, and increased power output.
Work done by a car engine can be measured using specialized equipment such as dynamometers or by using mathematical calculations based on engine specifications and operating conditions. It can also be estimated by measuring the engine's fuel consumption and converting it into energy units.