hello! I have been having a lot of trouble with one physics problem that I have for homework: any help would be greatly appreciated!
'A block of mass 12 kg starts from rest and slides a distance of 8 m down an inclined plane making an angle of 40 with the horizontal. The coefficient of sliding friction between the block and the plane is 0.4.
the acceleration of gravity is 9.8 m/s/s.
What is the net force on the block along the incline? answer in units of N.'
I think I am supposed to use acceleration-Fnet/mass. I just can't find the acceleration? I don't think it would be 9.8 because that's gravity and this object is not join straight down.
thanks!
You cant answer this unless you know the acceleration. If it slid at constant velocity, or you knew the time it took to go down, that would allow you to work it.
M*g = 12 * 9.8 = 117.6 N. = Wt. of block.
Fp = 117.6*sin40 = 75.59 N. = Force parallel with incline.
Fn = 117.6*cos40 = 90.09 N. = Normal force.
Fk =[ u*Fn = 0.4 * 90.09 = 36.0 N. = Force of kinetic friction.
Fnet = Fp-Fk = 75.59 - 36.0 = 39.6 N.
Hello! I'd be happy to help you with your physics problem.
To find the net force on the block along the incline, you'll need to break down the forces acting on the block.
First, let's find the component of the gravitational force that is parallel to the incline. This component will be responsible for the acceleration of the block along the incline.
The gravitational force acting on the block is given by:
F_gravity = mass * acceleration due to gravity
F_gravity = 12 kg * 9.8 m/s^2 (acceleration due to gravity)
F_gravity = 117.6 N
Now, let's find the force of friction acting on the block. The force of friction can be calculated using the formula:
F_friction = coefficient of sliding friction * normal force
To find the normal force, we need to resolve the gravitational force perpendicular to the incline. The normal force is equal in magnitude but opposite in direction to the component of the gravitational force perpendicular to the incline.
Normal force = mass * gravitational acceleration * cos(angle of incline)
Normal force = 12 kg * 9.8 m/s^2 * cos(40 degrees)
Normal force = 94.5 N
Now we can find the force of friction:
F_friction = 0.4 (coefficient of sliding friction) * 94.5 N (normal force)
F_friction = 37.8 N
Since the block is on an inclined plane, the force of friction opposes the motion of the block. Therefore, the net force acting on the block along the incline can be calculated by subtracting the force of friction from the component of the gravitational force parallel to the incline.
Net force = F_gravity_parallel - F_friction
Net force = 117.6 N - 37.8 N
Net force = 79.8 N
Therefore, the net force on the block along the incline is 79.8 N.
I hope this explanation helps you understand how to solve the problem! Let me know if you have any further questions.