Finding power without given speed or time

  • Thread starter Thread starter J51mustang
  • Start date Start date
  • Tags Tags
    Power Speed Time
Click For Summary
SUMMARY

The discussion centers on calculating the power developed by a lawn tractor moving up a hill at a constant velocity, given a mass of 120.0 kg and an incline angle of 21 degrees. The force acting down the slope was calculated using the formula mgsin(21), resulting in a force of 421.4 N. Due to the lack of velocity and time data, participants concluded that a symbolic answer is necessary, as there is insufficient information to derive a specific numerical value for power.

PREREQUISITES
  • Understanding of basic physics concepts, particularly forces and power calculations.
  • Familiarity with trigonometric functions, specifically sine for incline calculations.
  • Knowledge of Newton's laws of motion, especially regarding constant velocity scenarios.
  • Ability to manipulate equations symbolically when numerical values are missing.
NEXT STEPS
  • Research how to calculate power using the formula P = F * v, where F is force and v is velocity.
  • Learn about symbolic algebra techniques for solving physics problems with missing variables.
  • Explore the implications of constant velocity on force and power in physics.
  • Investigate additional methods for determining time in motion problems without direct velocity data.
USEFUL FOR

Students studying physics, particularly those tackling mechanics and power calculations, as well as educators looking for examples of problem-solving in scenarios with incomplete data.

J51mustang
Messages
1
Reaction score
0

Homework Statement


The lawn tractor in figure 18 goes up a hill at a constant velocity. Calculate the power that is developed by the tractor.
Mass: 120.0 kg
Angle of incline: 21 degrees
Distance: 12.0 m
Velocity: no velocity given other than it is constant
Time: idk

Homework Equations


None really

Just note that I used 9.8ms^-2 for acceleration due to gravity, NO value for velocity was given, and no time value was given.

The Attempt at a Solution


So I calculated the force in the direction of down the slop (by using mgsin21) and got a force of 421.4N, which means, since the acceleration in the dimension of the slope is 0ms^-2, that the net force is zero, meaning that the motor produces 421.4N of force. Now from here I’m stuck, as no value for velocity is given other than that it’s constant, and idk how to calculate time without velocity so that I could calculate power. Pls help.
 
Physics news on Phys.org
J51mustang said:
Mass: 120.0 kg
Angle of incline: 21 degrees
Distance: 12.0 m
Constant velocity
If that is all you are given then there is clearly not enough information. Make very sure there is no information you have overlooked. Some detail in the figure, perhaps?
 
Hi J51mustang,

Welcome to Physics Forums!

Since no velocity is given it looks like you'll have to provide a symbolic answer rather than a particular numerical result...
 

Similar threads

Rolling without slipping problem
  • · Replies 42 ·
2
Replies
42
Views
4K
Relating acceleration to distance and time
  • · Replies 5 ·
Replies
5
Views
3K
Having a hard time learning Newton's 2nd law
  • · Replies 5 ·
Replies
5
Views
2K
Find the power needed to accelerate this elevator downward
  • · Replies 4 ·
Replies
4
Views
2K
Finding the work done by a block
  • · Replies 4 ·
Replies
4
Views
3K
How can power and work be calculated using friction and known mass and distance?
  • · Replies 8 ·
Replies
8
Views
8K
Distance of projectile - only speed given
  • · Replies 4 ·
Replies
4
Views
2K
Help with question on motion: Avoiding a rear-end collision
  • · Replies 6 ·
Replies
6
Views
3K
Block on a Spring, Nonconstant Net Force
  • · Replies 6 ·
Replies
6
Views
2K
Find Projectile Flight Time Given Only Maximum Height
  • · Replies 4 ·
Replies
4
Views
3K