What is the frictional force acting on a car at 120 mph with a 30 hp engine?

  • Thread starter Thread starter KatieLynn
  • Start date Start date
  • Tags Tags
    Friction Work
Click For Summary

Homework Help Overview

The problem involves determining the frictional force acting on a car moving at a constant velocity of 120 mph, given that the engine produces 30 horsepower. The context includes concepts of power, force, and the relationship between them in the context of motion.

Discussion Character

  • Exploratory, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the relationship between power, force, and velocity, with one participant attempting to convert horsepower to watts and velocity to meters per second. Questions arise about the necessary units and whether to multiply or divide the values to find the force.

Discussion Status

The discussion is active, with participants exploring different approaches to relate power and force. Some guidance has been offered regarding unit conversions and the mathematical operations needed to find the frictional force, but there is no explicit consensus on the final approach yet.

Contextual Notes

Participants note the need for clarity on unit conversions and the relationship between power and force, indicating some uncertainty about the calculations required to arrive at the frictional force in Newtons.

KatieLynn
Messages
64
Reaction score
0

Homework Statement


When an automobile moves with constant velocity, the power developed is used to overcome the frictional forces exerted by the air and the road. If the engine develops 30 hp, what total frictional force acts on the car at 120 mph?


Homework Equations


1hp = 746W
1mile-1609m
work=force*distance
power= work/time

The Attempt at a Solution



30hp= 22380w
120mph= 53.6448m/s
I'm really not sure where to go from there, you need to end up with force which is Newtons, don't you need a mass in kg to for that?
 
Physics news on Phys.org
Power = Force*velocity.
 
so can you just multiply 22380w and 53.6448m/s, or do you have to change the watts to another unit?
 
oopps you have to divide them actually right?
 
Yes. No need to change anything.
 

Similar threads

Electric car and battery problem
  • · Replies 12 ·
Replies
12
Views
2K
Finding Frictional Force and Power Using Work and Energy
  • · Replies 4 ·
Replies
4
Views
3K
What is the magnitude of the force exerted by friction?
  • · Replies 4 ·
Replies
4
Views
8K
Power used to move a car up an incline with friction
  • · Replies 7 ·
Replies
7
Views
6K
Magnitude of total resistant force on a car?
  • · Replies 1 ·
Replies
1
Views
6K
Calculating Work Done by Car Engine
  • · Replies 8 ·
Replies
8
Views
2K
Does Static Friction Contribute to Work in an Inclined Car?
  • · Replies 4 ·
Replies
4
Views
3K
How Long Does It Take for a Car to Stop with Friction After Engine Shutdown?
  • · Replies 3 ·
Replies
3
Views
1K
What Is the Main Force Driving a Car's Acceleration?
  • · Replies 2 ·
Replies
2
Views
2K
What is the power of a car engine?
  • · Replies 6 ·
Replies
6
Views
2K