Forces acting on a car on an incline

AI Thread Summary
The discussion focuses on the forces acting on a car parked on a 1 in 30 incline, specifically calculating the normal force and the car's acceleration if the handbrake is released. The normal force is determined to be perpendicular to the incline, and the car would roll backward if the brake is disengaged. In the absence of friction, the car will slide down the slope regardless of the handbrake status, as the force parallel to the incline causes acceleration. The equation mgsin(θ) is used to express this acceleration. Overall, friction plays a crucial role in determining whether the car remains stationary or moves down the incline.
TheBigDig
Messages
65
Reaction score
2
Homework Statement
A 1100 kg car is parked on an incline of 1 in 30. What is the normal force acting on the car? In the absence of friction what would be the acceleration if the handbrake were released?
Relevant Equations
## \vec{F} = \mu_k \vec{N} ##
## F = mgsin\alpha ##
## N = mgcos\alpha ##
For part 1, I got ## tan \alpha = 1/30 ##
##\alpha = 1.9^{\circ}##
##mgcos(1.9) = 10774N##

I'm a little thrown off by the second part. Are we supposed to assume that in the absence of friction, F = N and then substitute F = ma to solve for this?
 
Physics news on Phys.org
TheBigDig said:
Homework Statement:: A 1100 kg car is parked on an incline of 1 in 30. What is the normal force acting on the car? In the absence of friction what would be the acceleration if the handbrake were released?
Relevant Equations:: ## \vec{F} = \mu_k \vec{N} ##
## F = mgsin\alpha ##
## F = mgcos\alpha ##

F = N
It would help if you were to distinguish forces in different directions instead of writing "F" in every case.
Which direction is the normal force? In which direction will the car move if the brake is released?
 
haruspex said:
It would help if you were to distinguish forces in different directions instead of writing "F" in every case.
Which direction is the normal force? In which direction will the car move if the brake is released?
Sorry yes of course. The normal force is perpendicular to the surface and the car will roll backward. I believe the model should correspond to this
main-qimg-1e095a892cea774cc9bbf38751a76228.png
 
The force acting parallel to the slope causes the car’s acceleration so, since F=ma, you have mgsin(θ)=ma so a=gsin(θ).
 
TheBigDig said:
Homework Statement:: A 1100 kg car is parked on an incline of 1 in 30. What is the normal force acting on the car? In the absence of friction what would be the acceleration if the handbrake were released?
If there is no friction, then whether the handbrake is on or not is irrelevant. The car will slide down the hill in any case.

If there is enough friction, then the handbrake will hold the car, but the car will roll down the hill if the handbrake is released.
 
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Back
Top