Can a Car Move Up a Hill with Only 30N of Frictional Force?

  • Thread starter Thread starter pb23me
  • Start date Start date
  • Tags Tags
    Torque
Join the discussion
Registration is free. Start your own thread to ask a follow-up.
2 replies · 2K views
pb23me
Messages
204
Reaction score
0

Homework Statement


A car is on a hill. A force of 100n is applied to the axel by the motor in order to move the wheel.The frictional force btwn the wheel and the street is 30N. will the car move up the hill?
also the radius of the axel is 10cm and the radius of the wheel is 20cm. the angle in the picture is 135 degrees

Homework Equations





The Attempt at a Solution

i drew a force diagram. see pic . i came up with 10MN being applied and 6MN for the torque of friction. so yes it does
 
Attachments
  • wheely.jpg
    wheely.jpg
    11.2 KB · Views: 383
  • force.jpg
    force.jpg
    13.8 KB · Views: 361
Physics news on Phys.org
Yes you are right. The car is able to climb!

Assuming the forces on the incline are balanced (ie net forces are zero. Since the mass is not given, we can't verify that. But since it is not given, it means that the forces are balanced and the car is not moving backward with the wheels spinning forward)

So equilibrium of the forces are assumed.

So it is a matter of how much torque is generated by the axle.

axle torque = 100 * 0.1 = 10Nm
Frictional torque = 30 * 0.2 = 6 NM

So obviously we have 10 - 6 = 4 Nm of torque that is available for acceleration!
 
But it is ridiculous that the frictional force that propels the car up hill is only 30N !
Looks like this is a toy car - cozy coupe :-)